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Adjusting the suspension - Madmax - 23-06-2009
This is an article about setting your suspension, both front and rear writting by Iceman de Pimpster a number of years ago. It's worth reading. Don't know if the pictures migrated or not.
Max
This long post is for those of you who may be like me and use/ride your Hayabusa as "The Ultimate Hyper Sport Tourer".
While the Busa is blessed with one he11 for power engine it's stock suspension leaves much to be desired by the curve slicing road warriors amoungst us. To wit?..it's front forks simply lack the same amount of travel normally found in full blown RR type sportbikes which to me means that it is that much more important that we make the most of what little suspension travel we do have. Also?...while attending this last Busa Bash at Deals Gap I promised a bunch of members here that when I did get the chance to properly address my new-to-me Busa's suspension that I would share that information here with the members of hayabusa.org...this is me fulfilling that promise.
"MOTORCYCLE SUSPENSION" is a deep subject...a physics ruled applied science with so much to know that I will only touch on the necessary parts of it here and be as concise as possible which will hopefully include enough information that you can make the most out of...
"ADJUSTING YOUR BUSA'S STOCK SUSPENSION FOR HIGH PERFORMANCE RIDING."
RULE #1: Forget everything the Service Manual or Owners Manual recomends as those settings and adjustments are extremely generic in nature and only meant as a starting point recomendation for riders of grossly varying and unknown weights...as in...ya might as well consult "The Guesser" at the county fair and in a word?..hooey...now here's how to do it the right way.
"Measuring Static/Sag": is really a misnomer as what you'll be measuring are these three suspension measurements (both front & rear)...
1. "Full Extension" (just what it implies..your forks and/or shock fully extended and this measurement is taken only for purposes of baseline reference)
2. "Static Sag"(or free sag...which is the amount of compressed travel under JUST the weight of the bike alone) and finally...
3. "Laden Sag" (the total amount of compressed travel with both the weight of the bike itself AND the rider aboard)
Note: "FULL EXTENTION" measurements are not 5to be confused with "Actual Suspension Travel" and are only for use as reference dimensions from which to base your sag settings from as already know that "The Actual Suspension Travel Specs" for the Hayabusa are...
FRONT: 4.7" (120mm)
REAR: 5.5" (140mm)
So do not confuse "Full Extension" with or assume that it is "Actual Suspension Travel".
The mission here is to attempt to compress approx. 33% (1/3rd) of the suspensions actual travel as "Laden Sag Compression" both front and rear. Lighter or Heavier riders may have to re-spring. I weigh 240 and will have to re-spring my front as it is way too soft but I was just barely able to attain *NEAR good performance settings by socking down the spring preload adjusters and stiffening up the compression rebound settings.
"THE FRONT FORKS"
With the 1 1/4" Genmar Riser I already had an added level of difficulty but it worked out to my advantage as instead of eye-balling the 8 engraved lines on the spring pre-load adjusters?...I counted revs by marking my 17mm socket and spinning them all the way out from flush for a total of 12 counted revolutions like so...
I had already measured the FULL EXTENDED distance of my front forks previousely (while the lower fairing was off and I had the front wheel freely suspended off the ground with the forks at full unladened extention) and that distance measured right at 5 inches from the bottom side of the dust cover to the top side of the cast fork end.
With the adjusters socked down too flush with the fork cap (max spring preload) my static sag dimension was 3.950"
With the adjusters spun out too 12 revs out (minimum spring preload) my static sag dimension measured 3.450...
which represented a full 1/2" of adjustability by tuning/setting the spring end play by using the spring preload adjusters. I settled on taking the preload adjusters a full 10 revs in (from 12 revs locked all the way out) to achieve a static sag dimension of 3.850"....or 1.150 static sag compression..which basically sux as just the static weight of the Busa itself has ate up 28mm of compression on me and I haven't even gotten around to plopping my lard@$$ on it yet...and now for the important part...
33% of 4.7" (actual travel) ='s 1.551 (as "Laden Sag" Compression)...
5" (FULL EXTENTION) - 1.551 = 3.449"
That's "The Magic Number" folks...PROPER LADEN SAG SHOULD BE 3.449 That's the measurement you want between the top of the cast fork end the the bottom of the fork seal dust cover..and measured as follows...with the bike resting static on a rear stand place a zip tie here like so...
Then gently mount the bike (while it's on it's rear stand) slowly lifting your feet to the pegs and assuming your riding position...then gently dismount the bike and then measure like so and HERE is where your looking to hit that magical 3.449 "Laden Sag" dimension...
As you can see it's apparent that I missed my magic number by about .300 and had about 7mm to much laden compression which indicates to me that the springs are too weak..as I suspected they would be due to the fact that the static weight of the bike itself had already gobbled up the lions share of compression before my @$$ ever hit the seat (and that's the impotance of taking "Static Sag" measurements)...and IMHO the Busa flat out needs stiffer springs up front...and that goes for anybody...sans any sub 150lb flyweights who might get away with using the stock oem fork springs..but I wouldn't recomend it..the Busa has proven to me it needs stiffer fork springs....and now the good news...
"ADDRESSING THE REAR SHOCK"
All the same factors previously discussed apply here as well and I had far better luck here...
The rear (like the front) seemed gushy and wallowy to me..especially when up at the Busa Bash...and here we go...
The first measurement needed is "Full Extension"...for this I had to devise a way to suspend the rear wheel in the air with the swingarm/shock unladened of any sprung weight...which I did like so...using a rear stand, a pair of jack stands and a length of 5/8ths steel rod...like so...
once the rear wheel/swingarm is freely suspended put a piece of electrical tape on the outboard most area of your ductail to use as a measuring reference point and measure from the top of the swingarm end flat like so...
And that's your "Fully Extended" measurment...now...before you lower the bike back down?..(and trust me here)...Page 36 of your owners manual will tell you that you need a special tool to adjust the shocks spring preload...they lied...just take a drift and a hammer and go in there and spin that top jam collar off the adjustment collar in a counter clockwise direction and put a dab of paint for a ref. starting point like so...
and then using your drift and hammer drift/spin the adjusting collar two full revs/threads downward (clockwise)...this will put an approx. additional 4 mm of preload on your shocks spring like so...
then lock that jam collar back down snugly and set your compression damping (top screw) at 7 clicks out and your rebound damping (bottom screw) at 10 clicks out...you'll love the results...or just do the math and tune to your own taste and body weight.
I know this...my Busa's suspension was way too soft and very vague feeling to me...I exploited the fork damping a bit to kinda cheat a tad and make up for the weak/soft fork springs by setting compression damping up front too just 4 clicks out and rebound damping to just 3 clicks out and even though I know my busa needs heavier front fork springs?...these adjustments and settings made a world of difference in how she handles now...no more squating in the rear under acceleration and she dosen't dive in the front (during hard braking) anywhere's near as badly as she used to..heck...just the massive torque and engine braking used to be able to have her rocking back and forth like riding a freaking hobby horse...but not anymore as just addressing sag dimensions and settings has proven to yeild a vast improvement...and now I just need to order slightly heavier fork springs.
You are all very welcome and for as much knowledge as I extract from this board for my own personal use I'm more than happy to be able to share some information myself. Furthermore...after my findings of just how softly sprung the Busa's stock/oem front forks are?... (28mm Static Compression is just waaay too soft)..I see this as a rather important issue...one that needs addressing because no matter how skilled of a rider anyone here may be?....if you run out of fork travel on a 500lb bike you are in deep pooh...no matter who you are.
I'll be calling around for heavier springs soon...possibly even today...if you guys do decide to make this a sticky I will maintain this thread by adding a small tutorial "How To" as I swap out to heavier springs.
Thanks again and L8R, Bill.
Update: I just got off the phone with some friends in the business whom I've had the rare privilage of briefly working alongside of and learning from...who also happen to be the same guys who set-up the suspension on Lee Shierts record holding Busa and Lee's latest 200+ '05 GSXR1000 project bike...to wit...Max MCcallister and Lee and Martin of "TRAXXION DYNAMICS" and when I ran my front fork sag dimensions by Lee just moments ago he was like.."My god...that's like cruiser suspension sag numbers!!! LOL!!!"...and I agree..and did what I already knew I should do and went ahead and ordered up a set of stiffer front fork springs to facilitate proper front end suspension of my Busa per my 240lb rider weight by selecting Lee and Martins recommendation of 1.1 rate Traxxion OMNI Springs which incorporate a nylon buffer/spacer system much like what is used in top level dirt bike suspension except..made and calibrated for the Busa whereby the nylon buffer slides over the internal cartridge rod and into the ID of the spring itself which entraps the fork spring central to the internal cartridge rod (so it dosen't mislocate center and wind up sqeaking against the fork tube ID) annnnd....prevents the spring from "Bowing In The Middle" when uder great load.
The 1.1 Straight Rate Omni Springs ran me $109...the buffer/spacer kit was $14.95 and the fork spring compressor tool was $29.95...all together about $160 including shipping...but money well spent considering the possible alternative as...when your screaming like a woman cause you came into the curve of a decreasing radius a little to hot is no time to decide to upgrade your Busa's suspenders!!! I'll just tell the wife it's "Cheap Insurance". LOL!!!
But seriousely folks...the good news is that the stock oem rear has plenty of support and travel for spirited riding (provided it's properly adjusted) but...the front suspension on the Busa sux...as not only is the overall usable fork travel shorter than what's on RR type sprtbikes?..but according to the static sag numbers it's also sprung far to soft...for anyone..and imho?...(and Lee's)..together that's a recipe for disaster.
Vman: I had to do something to safely keep up with your huge ultra fast @$$!!! LOL!!! BTW...In speaking with Lee at traxxion he asked if we had any heavy duty riders as Traxxion is trying to come up with proper spring weight dynamics on the busa's rear shock to adequately and proper advise/accomodate the heavier riders amoungst us...I mentioned that your one he11uva rider and looking to do future track days with your busa...and they need to get some baseline numbers by putting a stock oem rear shock spring on their "Spring Dyno"...call Lee at traxxion...tell'em Bill Jinks sent ya..I'm certain they'll be happy to have ya ship'em your rear shock and maybe cut ya a brake...if not at least give ya some great suspenders to match rider weight for you...I've been in the hot pits with Max and his crew at Daytonas CCS championships...they know their pooh.
L8R, Bill.
Yep....first screw both the compression ajustment (lower rear side of fork end casting) and rebound adjustment (little screw on top of spring preload adjusters) all the way IN till they stop..then...
REBOUND: 3 Clicks Out
COMPRESSION: 4 Clicks Out
and this is with your spring preload adjusters set at just 1 line showing...ie..socked all the way down too the first line.
My Rear Shock Settings Are...
Rebound (botton screw): 10 Clicks Out
Compression (top screw): 7 Clicks Out
And that's with two full revs more rear shock spring preload from stock factory adjustment.
L8R, Bill.
Him: To answer your 1st question?....sure...if you'd like to come down my way I could take you and your busa out to moroso here in west palm beach, fl (or fly me up to IL) and I could watch you launch a few times and make recomendations/adjustments to help you set-up your busa's suspension for optimum launchability..but that's not real practical or realistic so..to answer your 2nd question?...
Not really...as road racing settings and drag settings are two different worlds but maybe I could share some thoughts/knowledge here to maybe help you (and others here) to better understand the physics behind optimizing your suspension.
First one must understand that springs are springs and damping is damping...as follows...
Springs: only serve to support the bike and riders "sprung weight" but must be of the proper compression rate to "Optimize and Maximize The Suspensions Effective Working Travel".
Damping: yeilds a fluid feel to what is a mechanically spung suspension but it's primary purpose and use is to "Control Wheel/Spring Velocity" on a vertical plane in both directions of compression and rebound.
Drag racers need to find a happy medium balancing the scales between reducing both rear wheel spin AND keeping the front end down..and it dosen't help when a good tight hard launch dictates that the rider at the line applies front brakes to "load the clutch" which serves to slightly lift the rear while compressing the front...then as the yellow light flickers to green all that energy is suddenly released and reversed as the slightly raised rear trys to squat (from loaded and raised) and the preloaded front releases and rises...and DAMPING under these conditions can best be exploited by max damping up front (thereby decreasing rebound velocity and slowing down the rise of the front) and maximizing compression values in the rear to help slow down the squatting reaction..greatly reducing the transfer of weight from front to rear and lessening the bikes propensity to hoist the front wheel....a balancing act.
To help avoid wheel spin and breakking loose at launch some drag racers (pending technic) will actually be better served with a slightly softer rear suspension as this will help dampen "The Torque Hit" to the rear wheel and help the rear retain it's traction values...acting sort of like a buffer for the clutch impaired if you will. LOL!!!
But like I said...all bets are off when draggers start making drastic changes to the bikes suspension geometry with dogbones, straps and lengthened swingarms..and the best you can do there is tune for a happy medium between reducing wheelyability yet retaining maximum rear wheel traction levels.
Road Racing and Drag Racing...two very different suspension worlds and two extremely large cans of worms.
Hope that helps and L8R, Bill.
Chain...I'm ROTFLMAO right now...as here's the difs...
1. These are pro track jockeys just trying to suggest the best settings with the stock hardware...tuned by personal feel, taste and preference and NOT by the book or by the numbers...and...
2. I copied the following from the "Suspension Tuning Guide" link...
"This guide will help you gain a better grasp of your sportbike's suspension and how to dial it in to get the most out of your motorcycle. After all, having horsepower is one thing, but if you can't get it to the ground, you'd just as soon be better off on a 50cc moped. Read, learn and enjoy.
--Kent Kunitsugu
Chain..have you ever seen "Kent Kunitsugu"?
Well..really neither have I...at least not in person but in photo's he appears to be like 130lbs soaking wet...and a pro racer....trust me...our suspension requirements will vary.
Just his "Spring Preload" numbers tell the story...he's running 4 lines showing in the front and 15mm of thread showing on the top of the rear shock...my 240lb #'s?....I have my front fork preload socked down to 1 line showing and 20mm's of thread showing on the rear shock...as my 240lb @$$ needs way more spring than does Kent...and this is a prime example why I went to all the trouble of sharing here how to propery set sag dimensions as rider weights do vary so much...and if your 200+ or anywhere's near it?...you'll hate what kent loved and if you use Kents numbers your busa will seem extremely vague, wallowy, and unplanted.....tune your suspension TOO YOU...by the book...by the numbers..you'll be much happier, safer, more confident annnnd....faster.
L8R, Bill.
Quote (FAKK2 @ May 07 2005,21:32)
JINKSTER: I measured it out as being @230 wanting to loose weight so I am thinking of going with a 1.05kg springs on ohlins forks, and rear ohlins going to 14kg spring. what do you think?
I like it...you're moving up on the rear spring as the stocker is 13.1KG and I can get enough out of the stock rear at max preload but if I were you?...I'd go for the 1.1 fork springs for three reasons..
1. Going to a stiffer rear spring such as the 14kg is going to transfer much of the suspension action and weight right back up front again...(remember...anything you do to the rear affects the front and visa-versa)..amplifying any boingyness or weakness in the front springs as the 14kg rear will force the front to work harder and...
2. Imho you'll get far better feedback with the 1.1's and...
3. You'll have a greater amount of preload adjustment in reserve as the springs begin to age and sag.
Hope That Helps & L8R, Bill.
Quote (FAKK2 @ May 09 2005,02:29)
Quote (JINKSTER @ May 07 2005,21:48)
Quote (FAKK2 @ May 07 2005,21:32)
JINKSTER: I measured it out as being @230 wanting to loose weight so I am thinking of going with a 1.05kg springs on ohlins forks, and rear ohlins going to 14kg spring. what do you think?
I like it...you're moving up on the rear spring as the stocker is 13.1KG and I can get enough out of the stock rear at max preload but if I were you?...I'd go for the 1.1 fork springs for three reasons..
1. Going to a stiffer rear spring such as the 14kg is going to transfer much of the suspension action and weight right back up front again...(remember...anything you do to the rear affects the front and visa-versa)..amplifying any boingyness or weakness in the front springs as the 14kg rear will force the front to work harder and...
2. Imho you'll get far better feedback with the 1.1's and...
3. You'll have a greater amount of preload adjustment in reserve as the springs begin to age and sag.
Hope That Helps & L8R, Bill.
hmmm well 1.05 maybe good for this reason I am trying to loose weight I based this all on 250lb person in street cloths, now I am wanting 165-175 as weight so that maybe enough to componsate for 1.05kg front, and 14kg rear what do you think???
I think I'd still get the 1.1's and then celebrate losing 75lbs AFTER I lost it by spending another $100 for the 1.05's if I still felt I needed them..and then recover $50 selling off my 1.1's in the classifieds...meanwhile?...I'd spring my bike for..
"What I Weigh Now"
and not what I think I'm gonna weigh later.
Sorry...I'm all down with "the power of positive thinking" gig and all but reality dictates that you could ride a lot of miles in the time it takes to lose 75lbs...keep it real.
BTW...when you do lose that 75lbs?...your narrow @$$ ain't gonna appreciate that 14kg rear spring anymore...and that'll be the first "Good Sign"...my best to you and your efforts brother...I could stand to lose more than a few lbs myself.
L8R, Bill.
Quote (FAKK2 @ May 09 2005,13:35)
JINKSTER say I do not go 1.1kg but stay witht he 1.05kg and the 14kg rear spring, how would you sugest to set it up.. just out of curiousity???
Not to sound like a wise@$$ but to answer your question..
"I'd Set It Up By The Numbers"
i.e. after the new 1.05 and 14kg springs were installed I'd set the rear shock spring preload with 15mm of thread showing just as a starting point...then I'd use the front preload adjustment to "measure, adjust & set sag" on the forks as described in the initial post...then I'd get seriouse with setting the rear spring preload (again by measuring and setting sag)...and once I had the rear dialed in for sag?...I'd re-address the front just to double check and make sure I still had it right as whatever you do to the rear can and does have an affect on the front and visa-versa....as changes to one always influences the other.
I personally feel your wasting money on th 14kg rear spring..as your making an adequate spring even stiffer...and then your mis-matching things even further by under-ordering front springs...so now you have a overly sprung rear working hard against an undersprung front...but you seem rather insistant on doing this combo...and as far as damping goes?...I could never advise you on that as I do not have and never would recomend the spring combo you seem so instant on ordering and installing.
You've beat me to death on this fakk...I'm glad to help in anyway I can but as the old saying goes?..you can lead a horse to water but...it's you're bike man!!! LOL!!!
L8R, Bill.
Well my new Traxxion 1.1 Straight Rate Omni Spring Kit and Fork Spring Compressor Tool arrived at my doorstep yesterday so I'm getting ready to take things to the next level here.
One of the problems I encountered is decoding and/or cross-ref'ing Suzukis odd fork oil weight call-out of "L01"...and right now I'm thinking it's probably 10wt as stock but am going to Spectro 5w...this will require that I apply a tad more rebound damping but will allow the oil to flow faster through the stock valving thereby greatly reducing the frequency of "Hydraulic Lock" events during compression damping and spiking my wrists when riding over the sharp edged stuff so..between getting the too soft stock progressive rate springs out of there and installing properly sprung straight rate springs with a lighter weight fork oil my baby should be standing tall annnnd yeild far more compliance...schweeeeeeet.
L8R, Bill.
Quote (dm_gsxr @ May 11 2005,15:07)
I made the suggested changes for 210 lbs (I'm 198ish and with gear I'm sure I'm up around 210: 'stich, boots, backpack). I tried to adjust the collar around the rear spring but it was picking up some wicked damage from my drift (steel rod and aluminum collar). It was causing the tabs to mushroom a little. I got it to about 17mm showing which might be close to 18mm due to the mushrooming.
The ride in seemed to be stiffer in that I felt the road bumps a little more which was to be expected. When I got to a stop, the nose didn't dive near as much as it used to. Accelerating from the light and roll-ons made the bike feel like a jack-rabbit. No rocking back.
This weekend I'll be up in the mountains and carefully trying the twisties to see how much difference it made.
I'm going to check in on how much the actual collar adjusting tool costs. If it's not outrageous I'll probably get one.
I'll ride carefully to get used to it so I don't head off into the bushes on my first run
Thanks for the instructions.
Carl
Carl...I observed your riding first hand at the Busa Bash and it was readily apparent to me that you're a well seasoned rider with some seriouse skills....well..imho?...your skills are about to be seriously amplified as...your Busa should feel very stabil and planted with much higher feedback levels which will boost your confidence..(so be careful and don't get "Over-Confident" as these setting do seriousely upgrade the suspensions performance) as my busa now corners like a cat as compared too the stock settings.
btw..those shock collars are plated steel..and maybe I've done wrong here by not specifying that....
a. The rear must be "FULL SUSPENDED IN MID AIR" (a rear stand does not facilitate this as it supports the bike by it's own swingarm which still leaves the shock "loaded" under the bike weight)...that weight must be "RELIEVED" prior to attempting too make the shock spring preload adjustment.
and...
b. If you do use the "Hammer & Drift" method to adjust the shock collars?..."GENTLE TAPPING" (just enough to get it to move a little at a time) is the way to go..if you get over-anxiouse or observe "mushrooming of the tabs" you're getting too agressive...take it slow and easy does it..or better yet?...get the right tool...I'll be researching this in an effort tro find the correct spanner wrench to make this rear shock preload adjustment...or if someone finds it before me please feel free to post it here.
L8R, Bill.
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Location: Port Saint Lucie, FL Posted: May 11 2005,21:11
________________________________________
Gentlefolk...please consider this an addendum to the primary post here...
"THINGS YOU SHOULD KNOW ABOUT SPRINGS"
Very short, sweet and concise here...
The industry standard regarding "Tolerances For Spring Compression Rates" is +/- 5%. (but are typically held much closer than that)
What's this mean to you?: Spring to spring, bike too bike suspension settings can and will vary even amoungst riders of equal weight..to a degree..and THIS is why it is so important to set-up YOUR bikes suspension sag numbers TOO YOU and then fine tune to taste and/or personal preference. In this I myself strive to attain a good balance between "Bump Compliance" and "Suspension Performance" (whereby I'm attempting to minimize front end dive and rear end squat....what I call...."The Hobby Horse Affect")
which in turns greatly minimizes front too rear weight transfer during hard braking/acceleration manuvers making the bikes chassis far more stabil during aggressive riding.
To give you an idea?...the magic "laden sag" numbers I came up with by calculating 33% of the forks 4.7 inches of overall travel is 3.449.
Now...if you calculate in the industry standard tolerancing of +/- 5%?...theoretically...with different bikes at the same settings...
5% of 3.499 ='s .172 inches
so at max outboard tolerances our actual laden sag dimensions (even at the same settings) could vary as much as..
.172 (-5%) + .172 (+ 5%) ='s .344 inches max tolerance span on just the spring too spring tolerances alone.
So...this explains why optimum laden sag settings may vary from bike too bike even with riders of equal weight and...there's also naturally induced "Spring Sag" that takes place over time and use.
I figured I'd address that BEFORE anyone inquired.
L8R, Bill.
Quote (him @ May 14 2005,20:03)
Hey jinks or anyone i was just out working on the supension. my
full extension is =126 mm
static sag = 103 mm
laden sag = 100 mm
im 160lbs
i dont know what to do with the numbers from your post is 3.449 the number for everyone?
in this case my actual travel will be 26mm? which is one inch.... im trying to turn that one inch into 3.449 inches? Am i on the right track
him: either you're confused or you are confusing me but just to recap the terminology and their respective meanings..
Full Extension: This measurement is pretty much self explainatory and you got it right as you posted measuring 126mm's...(which is only 1mm off my rough inch measurement of 5"s...which is 125mm)..so we're on track there.
Static Sag: is how much compression you get with JUST the weight of the bike...and with my spring preload socked down to just one line showing?...I have a measurement on my busa of 3.850"s...so...5" - 3.850" (97.7mm) ='s 1.150" (or just over 29mm) "Static Compression".
Then with me sitting on the bike in riding position (with feet on the pegs) we have...
Laden Sag: where I get a measurement of 3.150" whereby..
5" (125mm) - 3.150" (80mm) ='s 1.850" (or 45mm's) worth of "Laden Compression"
Now..bear in mind that even though we "measure" 5"s or 126mm full extension?...we only actually have 4.7 inches of actual overall travel available to us...and 33% of 4.7"s ='s 1.551 (39.4 mm) as what is a desirable 33% laden compression and...33% is soft as compared to race sag where riders look for just 30mm's of laden compression...me?..I'm compressed 5+mm's too much...past the "desirable"....way too soft..and that's with my preload adjuster almost fully compressed.
Your numbers aren't making sense to me as there's no way the weight of your body is only compressing your forks a measly 3mms dif between static and laden sag.
L8R, Bill.
him: 89mm laden is a pretty good number as 126mm (extended) - 89mm (laden) ='s 37mm "Laden Sag Compression"..close enough..but what isn't making sense to me is that you posted measuring 92mm static..126 - 92 ='s 34mm "Static Sag Compression"...just 3mm less compression than Laden?...meaning the weight of your 160lb body is only compressing the forks a scant 3mm more than "Static"?
Something ain't jiving here.
L8R, Bill.
Quote (him @ May 15 2005,16:29)
when i get on the bike and get into my riding position it just doesnt move any. Is something to stiff? I dont know if the spacers or doing that. it seemed kinda strange to me. i took it for a ride doesnt feel strange at all. i havent gotten around to doing the back yet casue i wanted to handle the front but still. im not sure whats going on. if it means anyting my fork bolts(17mm ones ) are screwed out to 7 blocks?
Well..even taking into account that I'm 240 and you're only 160?..my body weight is causing an extra 15mm more compression when laden...and your's is only compressing 3mm when you get on?..dosen't make sense..even with the body weight delta between us you should still be getting at least an extra 10mm compression but you're only claiming/measuring 3mm.
Initially I thought..hey..meybe his comp damping screw is locked all the way in...but...that dosen't wash either cause if it were it would affect static as well and...it apparently isn't...you're getting plenty of static sag....almost exactly the same amount as my busa's static sag...but then laden my bodyweight compresses 15mm more and you only measure 3mm?
Somethings either not right and/or not getting measured right.
Back to top
Quote (him @ May 15 2005,17:27)
i can explain what i did and you let me know where i screwed up.
1 jacked teh bike up measured from boot to cast iron part 126mm
2 let the bike down measured from boot to cas iron 103mm
3 put twist tie on got on measured from top of tie to cast iron100mm
4 adjust 17mm bolts until my laden sag was just at 89 which is 3.449
Do i need to press or lean on the bars. i havent done my rear either could that have some effect on how low the bike drops when i get on it?
him: Just cause I can't explain why you're only getting 3mm more sag when laden as opposed to static dosen't mean "you screwed up"...matter of fact?..it sounds like your did everything just as described...I'm just baffled and left at a loss as to why your added body weight is only showing 3mm's more compression...as in...strange.
What are your rebound and compression settings adjusted at?
And just so ya know...the reason 3mms sounds weird to me is this...
Your Busa weighs maybe about 500lbs "wet"....figure about 300 of that is biased up front...and just the weight of the bike compresses it 29mms..then add your weight on top and it only compresses another 3mm's?
sumpt'ins funky...or..for some reason your suspension is "STACKING" like a biotch in that last 3mm's.
Gimme your damping #'s..comp & rebound...in "clicks out".
L8R, Bill.
Quote (him @ May 15 2005,20:03)
on the damping im 8 clicks on each from the stock setup to softer. i tried making it softer to make the bike compress more. i didnt really fool with taht too much though just the 8 clicks. it seemed like when i was clicking them nothing was happening as far as compression wasnt chainging so i stopped before i screwed something up.
Okay..well that explains a bit except for the "from the stock setup" part...do you mean to say you "added 8 clicks out" to the stock settings?
Also..what year is your busa?
and...
How many miles on it?
Cause it's all starting to sound to me like your upper range of suspension is completely mushed out...and that's why it's sagging so badly under static and then just a tad when you hop on.
"Time & Use" can cause your fork springs to sag out and get played out all on their own....matter of fact?...right in the shop manual there is a "minimum free length" on the fork springs...and anything under (240mm/9.4") should be replaced...and no doubt things like slamming down wheelies and/or strapping forks down for drag racing will greatly decrease a fork springs life span.
It's the only explaination I can offer at the moment...but one thing is for certain...if your static sag puts 29mm's of compression on your forks but the addition of your body weight only compresses them an additional 3mm's?....somethings definantly wrong with your suspension set-up.
L8R, Bill.
Quote (Charlesbusa @ May 16 2005,00:32)
Quote (JINKSTER @ May 11 2005,09:11)
Gentlefolk...please consider this an addendum to the primary post here...
"THINGS YOU SHOULD KNOW ABOUT SPRINGS"
Very short, sweet and concise here...
The industry standard regarding "Tolerances For Spring Compression Rates" is +/- 5%. (but are typically held much closer than that)
What's this mean to you?: Spring to spring, bike too bike suspension settings can and will vary even amoungst riders of equal weight..to a degree..and THIS is why it is so important to set-up YOUR bikes suspension sag numbers TOO YOU and then fine tune to taste and/or personal preference. In this I myself strive to attain a good balance between "Bump Compliance" and "Suspension Performance" (whereby I'm attempting to minimize front end dive and rear end squat....what I call...."The Hobby Horse Affect")
which in turns greatly minimizes front too rear weight transfer during hard braking/acceleration manuvers making the bikes chassis far more stabil during aggressive riding.
To give you an idea?...the magic "laden sag" numbers I came up with by calculating 33% of the forks 4.7 inches of overall travel is 3.449.
Now...if you calculate in the industry standard tolerancing of +/- 5%?...theoretically...with different bikes at the same settings...
5% of 3.499 ='s .172 inches
so at max outboard tolerances our actual laden sag dimensions (even at the same settings) could vary as much as..
.172 (-5%) + .172 (+ 5%) ='s .344 inches max tolerance span on just the spring too spring tolerances alone.
So...this explains why optimum laden sag settings may vary from bike too bike even with riders of equal weight and...there's also naturally induced "Spring Sag" that takes place over time and use.
I figured I'd address that BEFORE anyone inquired.
L8R, Bill.
So you're saying the laden sag measurement doesn't have to be exactly 3.449. It just has to fall between 3.277 and 3.621.
Is this a correct interpetation??
NO...It's not...not at all....I'm saying just what I said...springs (even at brand new manufactured) can have a delta/tolerance of +/- 5% compression rate wise...my span of 3.277-3.621 was just to show what sort of differential could be encountered just in the manufacturing varience of the springs themselves...to expalin why the same settings may not be optimum "busa-too-busa" and to stress why it is so important that...
You measure off, then set and adjust "YOUR BUSA's" static/sag #'s too "YOU"!
to attain the 3.449 dimension...33% of your busa's 4.7" fork travel....despite what "The Settings" of others may be.
Since there seems to be some confusion here I guess I should simplify things with the following...
30mm's Laden Sag is desirable for track day/racers and 40mm Laden Sag is THE MAXIMUM I would suggest for those desiring a plusher streetbike/sport touring ride...and personally speaking?...because the Busa's front forks are neutered to a scant 4.7 inches of "Overall Travel" (where most other sportbikes have about 5.5"s of overall travel) I'd advise erring more towards the 30mm end of things...but with me at 240LBS?...I can't get any better than 45mm Laden Sag with the stock springs as they are far too soft...making my busa too softly sprung up front to facilitate optimum suspension/handling.
L8R, Bill.
Quote (Charlesbusa @ May 16 2005,00:46)
Hey JINKSTER, great info. Question though;
You've explained how to setup/adjust preload based on rider body weight(basically). However, you recommended some settings for compression and rebound but they appear to be settings for someone close to your weight. I understand that suspension is all about rider preference. But is there a way to adjust compression and rebound by the book similar to the way you described how to adjust preload.
Thanks,
Charles
Unfortunately?...Not that I'm aware of Charles...but what I can share is what I look for which is...
Front Forks:
Compression Damping: I try to set compression damping as tightly as I can to....
a. reduce as much "Front End Dive" under hard braking as possible yet...
b. Not get it so tight that I'm spiking my own wrists when encountering road imperfections/bumps.
In other words...I want it tight enough that my front end feels planted and renders great feedback yet compliant enough to soak up the sharp edged stuff.
Rebound Damping: Just the opposite of comp. damping above?...Here I'm watching to make certain that my front forks aren't RISING excessively quick under hard acceleration..if they do?..I add rebound damping by turning clicks inward (Clockwise: which closes up the bypass ports forcing more damping affect) also...
I check for to much rebound damping by simply standing alongside of the bike and PULLING UP on the bars...and if I can get it to come up a 1/4-1/2 inch or so and it stays there?..chances are the bike is suffering too much rebound damping..and the rebound damping isn't allowing the suspension to fully return to full static suspension...and I'll reduce rebound by clicking the rebound screw out (Counter-Clockwise: which opens up the bypass ports reducing the damping affect)
Same with the rear shock...dose that help?
L8R, Bill.
Quote (hbus1300 @ May 16 2005,06:58)
Bill,
After reading your post I felt compelled to call Traxxion Dynamics, especially since I will be going to the Gap this month and dont want any suspension surprises while i'm there. I'm 280lbs and Lee is setting me up with a 1.15 front and I have sent them my rear shock as well. Figured I might as well get everything set up as well as I can without buying ohlins or penske stuff. Lee said though that they might have to revalve my rear shock because of the newer stiffer spring and the stock valving might not be able to control the rebound. They are going to put on the new spring and see how it works out, apparently they have a shock dyno to check it on. But, if it isnt going to be right he said to go through the rear shock it will be around $300 to get it right. While still half the price of the cheapest penske I wonder if it wouldnt be worth springing for the penske anyways. Anyways, are you considering doing your rear shock or have you known anyone who has and how has it worked out? I would hate to spend the $ modifing the stock shock then wish I bought the penske. Is there any other advice you could give someone going to the gap for the first time? Other good rides to go on in the area?
Jeremy.
No...I'm not considering doing anything with my rear shock...that part i lucked out on and at 240 LBS with the spring at max preload it seems to take sag settings just fine..for me..for now.
Penske shocks are 1st class but carry a huge price tag...if money wasn't an issue in my life and I planned on keeping the bike a good long while yet?...I'd maybe splurge on the penske.
That said?...If money was an issue in my life and I needed to be wise of wallet?..there's not a damn thing wrong with a properly rebuilt/revalved stock/oem shock..especially one that's been on a shock dyno to be custom sprung and valved for you and your bike..the only thing missing as opposed to the penske will be the remote gas damping adjust/cylinder.
Note: Ya might wanna ask Max, Martin or Lee at traxxion about the possibility of "ELKA" having a replcement model shock for the busa...theuy would be priced somewhere's between a oem rebuild and the penske..with a remote gas/damping adjust...yet another option worth consideration.
Outside of that? I believe you're gonna be pleasantly surprised how well your Busa handles after it's properly sprung and suspended..custom tuned to your weight range.
As far as advice on the gap goes?...be very careful on the dragon...it's extremely tight and technical and more suited to a 250 Ninja than a busa...Cherohola is funner but watch for popo and the decreasing radius turn at mile marker 11..."The Foothills Parkway" rox and is ideal for the Busa...143 into 28 out of Robbinsville leading into Fontana and the CROT (cross roads of time) is an excellent run as well.
L8R, Bill.
Quote (him @ May 15 2005,23:07)
For teh preload its 8 clicks softer than stock. the busa is a 2001 with just over 9k. i got the bike with 2800 on it. From the way the tires, chain and everyting looked i am the only one who beat the shid out of it. So i need to replace the springs in my forks how hard/expensive is that?
Expense: I paid $161 to traxxion for their 1.1 Omni Spring Kit which included...
$105 for the set of 1.1 straight rate springs
$14.95 for the Omni Buffer/Spacer Kit
$29.95 for a Fork Spring Compressor Tool (needed to do the job)
Plus shipping came to $161.
Level Of Difficulty: I'll be changing mine out in the next day or two and doing a step-by-step to post here...front end of the bike needs to be proped up to get the forks off...and I don't have a steering stem style front stand so...that'll be the toughest part to figure out but outside of that should be a piece of cake.
L8R, Bill
Quote (him @ May 16 2005,17:11)
ill wait till you do yoru write up and sell myself for the cash needed. Is there anything cheaper or is that the cheapest springs?
If your looking for "Cheap" you might try racetech as they don't offer anything like the omni buffer kit (which is only $14.95 and imho money well spent) but even racetech springs and spacers are gonna cost very close too the same and no matter who's springs you go with you're gonna need the spring compressor tool...(which is of great use on any USD fork)..or?..you can toss it in the classifieds after you're done using it to recoup some cash I guess...but...I'm keeping mine.
BTW....fork oil dosen't last forever either...according to the pro's it should be changed out every 10K miles or 2 years..and I've changed enough old fork oil to believe that.
Also... far better damping quality/compliance can be achieved (with the stock valving) by switching up too a lighter weight fork oil...I'm going with "Spectro 5W" as me and my associates believe the LO1 suzuki callout to be 10W stock fork oil...5W will flow quicker through the stock valving....yeilding "quicker hydraulic crosstalk" between damping and helping to reduce "hydraulic lock" on compression damping over sharp edged road imperfections.
I'll take a bunch of pix as I go which should help ya'll to gain a far better understanding of "The Whats & Why's"....and then I'll even show, describe and explain the difs and advantages between "Progressive VS Straight Rate" fork springs.
L8R, Bill.
Quote (Charlesbusa @ May 17 2005,00:57)
Quote (JINKSTER @ May 15 2005,19:07)
Charles...here's two excellent articles that word things probably much clearer than I can...
http://www.motorcyclistonline.com/howto/suspensionadjust/
and...
http://www.sportrider.com/tech/146_9604_tech/
Some light reading never hurt anybody!
L8R, Bill.
The 2nd link has better info that I was looking for. They made a little chart(below) that describes some factors and how they relate. Unfortunately, damping is a "feel" thing with no measurements to take or see. It'd be great to know exactly how much damping provides the best traction and feeling of control. So I guess its trial and error with some advice for initial settings is all we have to work with...
JINKSTER do you know of or can you recommend any damping settings for a certain body weight and certain Preload with stock suzuki suspension? I doubt Suzuki has recommended damping settings based on different body weights and different Preloads.
Charles...I wish I did but I don't..and as you saw/read in the articles the damping adjustments aren't even linear..as the article touched on the fact that you do not get "Same/Same" for each click..and that typically the first few clicks yield far more bypass value than do the last few clicks.
Another aspect that many seem to overlook is this...
"Increased Rider Weight Can Actually Seem To 'ACT' As More Compression Damping"
In other words...the heavier a riders body weight is?..the more affect it will have on readily subduing a spring..into what feels like a damped state..like when you take on a pillion rider..and the spring compresses itself into a higher stacked compression rate...and then suddenly your bike "feels" more solid and planted...as the added rider weight is now serving to add a damped feel to the springs compression and rebound because...
a. It's more compressed under load and..
b. It's not able to REBOUND and recover quite as quickly under the weight of two riders vs one.
So everything becomes a variable...with only "suggested" starting points from which to begin the suspension tuning process from...and all the pro's do agree on one thing...the best place to start is with a properly sprung bike..by setting static sag #'s accordingly...with adjustments made via spring preload or (if necessary) by swapping out springs to attain appropriate compression rates...and then and only then can "the damping tuning" process begin in an accurate fashion...preferably 1 click at a time..whilst keeping in mind that the first few clicks yeild the most affect.
And this is where the "Straight Rate Springs" shine over "Progressive Rate Springs" as while the progressive rate springs build and stack up much quicker than the straight rate springs?...it is that very progressive nature which makes them so difficult to attain proper sag and damping...as "The Sweet Spot Of Travel" is greatly diminished with the progressive rate springs...as you attempt to adjust what is "FINITE" damping values...and this is where progressive rate springs can make a suspension tuning perfectionist pull his freaking hair out as opposed to tuning what is finite damping for the "far easier to tune" straight rate springs...which will yeild a far greater...
"Sweet Spot Of Travel"
L8R, Bill.
Quote (valium @ July 09 2005,01:42)
JINKSTER
Im a 215Lb - 5'11" rider. I used your suspension settings for my 05 Busa today and dig the new setup but have a few questions for you. Here are my settings.
Im getting some different settings on my front Preload than you. I used a 17mm socket, marked a line on the socket, and find Im getting about 15 full Revs before I'm full out. You stated I believe 12 is full out. so I did it a few times and got the same results. Am I measuring wrong- First full turn I count as 1 and when I get to 10 revs, I counted 10 full revs / thus starting with another rev would be working on 11. Im also finding that when I'm bottomed out on my Preload I see that my left and right side compression adjusters when set at zero do not share the same vertical/ horizontal pattern - is this normal---meaning both lines are not level with eachother, but both are still bottomed out.
Also, in reguards to compression and rebound, when bottomed out, do you count that as 1, or your are you counting your first click as 1?
so here are my settings, should I change anything, am I running to much pre-load on the front?
Front Preload- 12 Revs In ( As stated it seems like I have a full 15 Revs in from bottom)
Compression - 4 clicks out
Rebound- 3 clicks out
Rear Preload- 2 full Revs on the collar clockwise
Compression- 7 clicks out
Dampening- 10 clicks out
I Very much appreciate all your time, I read this thread about 6 times, and found this information and your pictures completely awesome. Thanks for helping a guy out.
Valium, while not "probable"...It's very possible that there may be a rev or two difference in the fork preload adjust from bike too bike, fork too fork but...it might also be noted that the reason I chose to back'em out and "couint in" and didn't "go the other way" (by locking'em all the way down and then counting ccw revs out) is because....
a. As mentioned I personally had an added level of difficulty due to my preload adjusters being buried in my 1 1/4" genmar riser and...
b. When I did come close to "locked down" the champher on top of the preload adjusters 17mm hex was dangerously close to allowing my 17mm socket to slip on the nut champher...and screwing up the gold anodize finish...so I opted to NOT advise folks they screw'em all the way in/down as I didn't want that happening to them...and is why I advised counting revs FROM...all the way "Backed Out".
My advise here is not to be so concerned about how many revs your preload has but to concentrate on attaining proper static/sag settings/dimensions.
"Also, in reguards to compression and rebound, when bottomed out, do you count that as 1, or your are you counting your first click as 1?"
Backing off from "full bottomed out" the first click I hear I count as (1) as...when you are fully bottomed out that means that the internal needle valve is at "hard home"..and the hydraulic flow is theoretically completely sealed off..so...the first click out is (1).
"so here are my settings, should I change anything, am I running to much pre-load on the front?"
Only you can answer that...and it could be answered correctly by recording your static/sag dimensions as prescribed in this thread.
+/- .100"/3mm is no big deal....but for those of us who are only "coming close" by "almost locking down" our spring preload?...chances are you'd be far better served by properly re-springing your busa with heavier rated straight rate springs.
Also (just as a reminder)...most of your comp. and rebound adjusment range in your adjusters is located within the first few clicks of adjustment...as the further out you go the less affect each individual click will have....and this is stereotypical of hydraulic needle valve applications.
Just the fact that so many seem thrilled with the results of tightening up their spring preload adjustments tells me that most here (including myself) would be far better served by installing heavier rate springs in their stock busa's suspension....front & rear.
L8R, Bill.
Quote (pure_ego @ Aug. 11 2005,12:46)
Guys...
I'm gonna say something that Jinkster shoulda said awhile back.. (IMO) ... all the material you need to do this is right there on the front page...
simple asking him what to set your suspension too isn't going to teach you anything.. if you learn how to do it yourself... using the numbers, theories he took the time to type up will be a much better plan of action..
that way you will already know what your doing on your next bike.
For the record.. I did the 'busa... big improvement.... especially in front end dive.. ..
and I also set up the SV using the same formula.. just different numbers for the suspension travel and such for the different bike..
that one was closer than the 'busa.. so not as big a change... but it still helped..
anyway.. stop asking questions when all the answers are there for you to find on your own.
If you have a specific question thats cool... but to make all the work he did on those posts go to waste by simply asking what to set your bike too.. is not a very good way to show thanks.
Thanks Jinks... finally a suspension set up guide that I understood.. !!
Thank You PE.....well said...I just didn't wanna say the same and be a turn off...and enjoy...happy I could contribute something of value to this great community.
L8R, Bill.
RE: Adjusting the suspension - Masterbusa - 24-06-2009
Here is the same document but with the pics.
This long post is for those of you who may be like me and use/ride your Hayabusa as "The Ultimate Hyper Sport Tourer".
While the Busa is blessed with one he11 for power engine it's stock suspension leaves much to be desired by the curve slicing road warriors amoungst us. To wit?..it's front forks simply lack the same amount of travel normally found in full blown RR type sportbikes which to me means that it is that much more important that we make the most of what little suspension travel we do have. Also?...while attending this last Busa Bash at Deals Gap I promised a bunch of members here that when I did get the chance to properly address my new-to-me Busa's suspension that I would share that information here with the members of hayabusa.org...this is me fulfilling that promise.
"MOTORCYCLE SUSPENSION" is a deep subject...a physics ruled applied science with so much to know that I will only touch on the necessary parts of it here and be as concise as possible which will hopefully include enough information that you can make the most out of...
"ADJUSTING YOUR BUSA'S STOCK SUSPENSION FOR HIGH PERFORMANCE RIDING."
RULE #1: Forget everything the Service Manual or Owners Manual recomends as those settings and adjustments are extremely generic in nature and only meant as a starting point recomendation for riders of grossly varying and unknown weights...as in...ya might as well consult "The Guesser" at the county fair and in a word?..hooey...now here's how to do it the right way.
"Measuring Static/Sag": is really a misnomer as what you'll be measuring are these three suspension measurements (both front & rear)...
1. "Full Extension" (just what it implies..your forks and/or shock fully extended and this measurement is taken only for purposes of baseline reference)
2. "Static Sag"(or free sag...which is the amount of compressed travel under JUST the weight of the bike alone) and finally...
3. "Laden Sag" (the total amount of compressed travel with both the weight of the bike itself AND the rider aboard)
Note: "FULL EXTENTION" measurements are not 5to be confused with "Actual Suspension Travel" and are only for use as reference dimensions from which to base your sag settings from as already know that "The Actual Suspension Travel Specs" for the Hayabusa are...
FRONT: 4.7" (120mm)
REAR: 5.5" (140mm)
So do not confuse "Full Extension" with or assume that it is "Actual Suspension Travel".
The mission here is to attempt to compress approx. 33% (1/3rd) of the suspensions actual travel as "Laden Sag Compression" both front and rear. Lighter or Heavier riders may have to re-spring. I weigh 240 and will have to re-spring my front as it is way too soft but I was just barely able to attain *NEAR good performance settings by socking down the spring preload adjusters and stiffening up the compression rebound settings.
"THE FRONT FORKS"
With the 1 1/4" Genmar Riser I already had an added level of difficulty but it worked out to my advantage as instead of eye-balling the 8 engraved lines on the spring pre-load adjusters?...I counted revs by marking my 17mm socket and spinning them all the way out from flush for a total of 12 counted revolutions like so...
I had already measured the FULL EXTENDED distance of my front forks previousely (while the lower fairing was off and I had the front wheel freely suspended off the ground with the forks at full unladened extention) and that distance measured right at 5 inches from the bottom side of the dust cover to the top side of the cast fork end.
With the adjusters socked down too flush with the fork cap (max spring preload) my static sag dimension was 3.950"
With the adjusters spun out too 12 revs out (minimum spring preload) my static sag dimension measured 3.450...
which represented a full 1/2" of adjustability by tuning/setting the spring end play by using the spring preload adjusters. I settled on taking the preload adjusters a full 10 revs in (from 12 revs locked all the way out) to achieve a static sag dimension of 3.850"....or 1.150 static sag compression..which basically sux as just the static weight of the Busa itself has ate up 28mm of compression on me and I haven't even gotten around to plopping my lard@$$ on it yet...and now for the important part...
33% of 4.7" (actual travel) ='s 1.551 (as "Laden Sag" Compression)...
5" (FULL EXTENTION) - 1.551 = 3.449"
That's "The Magic Number" folks...PROPER LADEN SAG SHOULD BE 3.449 That's the measurement you want between the top of the cast fork end the the bottom of the fork seal dust cover..and measured as follows...with the bike resting static on a rear stand place a zip tie here like so...
Then gently mount the bike (while it's on it's rear stand) slowly lifting your feet to the pegs and assuming your riding position...then gently dismount the bike and then measure like so and HERE is where your looking to hit that magical 3.449 "Laden Sag" dimension...
As you can see it's apparent that I missed my magic number by about .300 and had about 7mm to much laden compression which indicates to me that the springs are too weak..as I suspected they would be due to the fact that the static weight of the bike itself had already gobbled up the lions share of compression before my @$$ ever hit the seat (and that's the impotance of taking "Static Sag" measurements)...and IMHO the Busa flat out needs stiffer springs up front...and that goes for anybody...sans any sub 150lb flyweights who might get away with using the stock oem fork springs..but I wouldn't recomend it..the Busa has proven to me it needs stiffer fork springs....and now the good news...
"ADDRESSING THE REAR SHOCK"
All the same factors previously discussed apply here as well and I had far better luck here...
The rear (like the front) seemed gushy and wallowy to me..especially when up at the Busa Bash...and here we go...
The first measurement needed is "Full Extension"...for this I had to devise a way to suspend the rear wheel in the air with the swingarm/shock unladened of any sprung weight...which I did like so...using a rear stand, a pair of jack stands and a length of 5/8ths steel rod...like so...
once the rear wheel/swingarm is freely suspended put a piece of electrical tape on the outboard most area of your ductail to use as a measuring reference point and measure from the top of the swingarm end flat like so...
And that's your "Fully Extended" measurment...now...before you lower the bike back down?..(and trust me here)...Page 36 of your owners manual will tell you that you need a special tool to adjust the shocks spring preload...they lied...just take a drift and a hammer and go in there and spin that top jam collar off the adjustment collar in a counter clockwise direction and put a dab of paint for a ref. starting point like so...
and then using your drift and hammer drift/spin the adjusting collar two full revs/threads downward (clockwise)...this will put an approx. additional 4 mm of preload on your shocks spring like so...
then lock that jam collar back down snugly and set your compression damping (top screw) at 7 clicks out and your rebound damping (bottom screw) at 10 clicks out...you'll love the results...or just do the math and tune to your own taste and body weight.
I know this...my Busa's suspension was way too soft and very vague feeling to me...I exploited the fork damping a bit to kinda cheat a tad and make up for the weak/soft fork springs by setting compression damping up front too just 4 clicks out and rebound damping to just 3 clicks out and even though I know my busa needs heavier front fork springs?...these adjustments and settings made a world of difference in how she handles now...no more squating in the rear under acceleration and she dosen't dive in the front (during hard braking) anywhere's near as badly as she used to..heck...just the massive torque and engine braking used to be able to have her rocking back and forth like riding a freaking hobby horse...but not anymore as just addressing sag dimensions and settings has proven to yeild a vast improvement...and now I just need to order slightly heavier fork springs.
You are all very welcome and for as much knowledge as I extract from this board for my own personal use I'm more than happy to be able to share some information myself. Furthermore...after my findings of just how softly sprung the Busa's stock/oem front forks are?... (28mm Static Compression is just waaay too soft)..I see this as a rather important issue...one that needs addressing because no matter how skilled of a rider anyone here may be?....if you run out of fork travel on a 500lb bike you are in deep pooh...no matter who you are.
I'll be calling around for heavier springs soon...possibly even today...if you guys do decide to make this a sticky I will maintain this thread by adding a small tutorial "How To" as I swap out to heavier springs.
Thanks again and L8R, Bill. Your browser may not support display of this image.
Update: I just got off the phone with some friends in the business whom I've had the rare privilage of briefly working alongside of and learning from...who also happen to be the same guys who set-up the suspension on Lee Shierts record holding Busa and Lee's latest 200+ '05 GSXR1000 project bike...to wit...Max MCcallister and Lee and Martin of "TRAXXION DYNAMICS" and when I ran my front fork sag dimensions by Lee just moments ago he was like.."My god...that's like cruiser suspension sag numbers!!! LOL!!!"...and I agree..and did what I already knew I should do and went ahead and ordered up a set of stiffer front fork springs to facilitate proper front end suspension of my Busa per my 240lb rider weight by selecting Lee and Martins recommendation of 1.1 rate Traxxion OMNI Springs which incorporate a nylon buffer/spacer system much like what is used in top level dirt bike suspension except..made and calibrated for the Busa whereby the nylon buffer slides over the internal cartridge rod and into the ID of the spring itself which entraps the fork spring central to the internal cartridge rod (so it dosen't mislocate center and wind up sqeaking against the fork tube ID) annnnd....prevents the spring from "Bowing In The Middle" when uder great load.
The 1.1 Straight Rate Omni Springs ran me $109...the buffer/spacer kit was $14.95 and the fork spring compressor tool was $29.95...all together about $160 including shipping...but money well spent considering the possible alternative as...when your screaming like a woman cause you came into the curve of a decreasing radius a little to hot is no time to decide to upgrade your Busa's suspenders!!! I'll just tell the wife it's "Cheap Insurance". LOL!!!
But seriousely folks...the good news is that the stock oem rear has plenty of support and travel for spirited riding (provided it's properly adjusted) but...the front suspension on the Busa sux...as not only is the overall usable fork travel shorter than what's on RR type sprtbikes?..but according to the static sag numbers it's also sprung far to soft...for anyone..and imho?...(and Lee's)..together that's a recipe for disaster.
Vman: I had to do something to safely keep up with your huge ultra fast @$$!!! LOL!!! BTW...In speaking with Lee at traxxion he asked if we had any heavy duty riders as Traxxion is trying to come up with proper spring weight dynamics on the busa's rear shock to adequately and proper advise/accomodate the heavier riders amoungst us...I mentioned that your one he11uva rider and looking to do future track days with your busa...and they need to get some baseline numbers by putting a stock oem rear shock spring on their "Spring Dyno"...call Lee at traxxion...tell'em Bill Jinks sent ya..I'm certain they'll be happy to have ya ship'em your rear shock and maybe cut ya a brake...if not at least give ya some great suspenders to match rider weight for you...I've been in the hot pits with Max and his crew at Daytonas CCS championships...they know their pooh.
L8R, Bill.
RE: Adjusting the suspension - Madmax - 24-06-2009
(24-06-2009, 01:52pm)Masterbusa Wrote: Here is the same document but with the pics.
Thanks Ryan, love your work!
RE: Adjusting the suspension - Gnarbunkle99 - 25-06-2009
Needs to be a sticky!
RE: Adjusting the suspension - RyanG - 12-06-2011
Awesome info. Thanks guys
RE: Adjusting the suspension - Bill Gaheer - 12-06-2011
(25-06-2009, 07:22am)Gnarbunkle99 Wrote: Needs to be a sticky!
Done
RE: Adjusting the suspension - Greeny_SA - 13-06-2011
Don't know about interstate ,but we have a suspension guru who will do all that for you for 30 buck's . Bargain ,don't even get your hand's dirty .