GIMME MORE THRUST!
#1
G`day troops.
Coming a little late on the scene,I don`t know if this subject has been covered before.
Has anyone else tried lowering the gearing by increasing the rear sprocket teeth to 43 from the std 40?There was a pretty good article about it in the UK mag"Performance Bikes"a while back.
I tried it a cuppla mths ago and....FAIR DINKUM!....the huge increase in thrust is devastating. (Senor S.Gonzales would truly be impressed,eh Pete?)(fellow cartoon connoisseur.)
We all already kno of course,the amazing torque/power of the busa,but with this small mod(Renthal sproc $70)it lifts the busa to yet another level.
I kno it lowers the top end to a piddling 295kmh or so(how often are we up there anyway,compared to the mid-range?) It`s a bit revvy at high cruising speeds but not to the point of being annoying.& the speedo`s out of whack(reads a bit high,but surely,this can only be a good thing,methinx,considering our constant,mutual endeavours at preserving our licences,huh?)
I`m really not that technically/mechanically minded,but I kno what I like,and....DAMMIT!...I like this!
Can anyone see any future problems arrising from this mod? Or perhaps some thoughts?
Cheers Franko
PS:Am I in the right cubby hole for this subject?
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#2
Curious....

1/ What is the max top speed with a 43 sprocket?

2/ Speedo correction can be made with a yellowbox, right?

3/ That shortens the wheelbase, doesn't it, and makes it handle better???

As I never do 300, I'd be better off making it quicker down low, and for the sake of $70, it's worth a try anyway.

Peter Altas
BUSA-1
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#3
1/ I pulled a genuine 300kmh a cuppla yrs ago across the Hay Plains.Not many other places one getz that sort of opportunity tho. & now,like you,I getz my jollies thru the mid-range.I`ve read,with the mod,they`re still pulling 290+.
2/ A mate on an SP-2 with the lower gearing,has fitted that yellow-box.Seems to me it`s a waste of time & $$.& something else that can screw with the bike`s electrics.I don`t thing a speedo reading a bit high is a prob.
3/Yep,it does shorten the wheelbase & with my high profile D208s it tips in real quick.I luv it!
4/For 70 pesos,its an inexpencive but a really great experiment.I guarantee you`ll luv it too,Peter.
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#4
I suppose that people still believe you're on a +300km/h machine, but you'll just blow away more cars/bikes quicker. Who continues a drag beyond 200? Most cars can't even do that safely.

Yep, next tire change (Pirelli Super Corsa's) I'll change the rear sprocket too. Why not. Don't trust the Briggies though. Still not confident through the corners with the stock tyres.
Peter Altas
BUSA-1
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#5
There are two types of people.Those who ride busas,and those who don`t(poor misguided fools!).They still try to shape up to you at the lights,don`t they?
Not always,but from time to time,its our solemn duty to put them in their rightful place,eh?(a rapidly disappearing dot in your mirrors!)
The BT56s were ok for a while,but now,as offered by most good sports tyres,we`re all looking for that seriuos gip on the edges.Of course,a good wear factor is a bonus.Not much chop tippy-toing round a bend and then saying"..yeah,but look how long it lasts."
GIMME THRUST & GIMME GRIP any day!
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#6
You wouldn't believe how many Honda CBR250's I get around here that want to go me, and the odd (muslim origin) in a commodore/wrx/datty 200b that thinks they have a warp drive lever on the dash like the Millennium Falcon.
(not racist, just there are alot of muslims around the Broadmeadows area)

Poor fools. My take offs aren't that quick, but I like to stay kinda level with them for a bit, maybe even back off so I can read their rego (and be sure that they're not an unmarked copper), then f*** 'em. I love screaming past them as I rev out first and second clicks home. Then at around 150ish, I'll back off and check the look on their faces. Most of the time I get a thumbs-up and a big grin.

The best was a guy in a skyline r33 gts-t. He said at the next set of lights that he knew he had no chance, but just wanted to see how fast I'd pull away.

Some people just need to be put in their place... quickly.
Peter Altas
BUSA-1
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#7
Another point, most tyres thesedays (excluding the Briggies BT56 J spec) arent rated above 300km/h. Last thing I need is to do a 300+ km/h run and have the tyres give way.

If I change the sprocket and prevent the +300, at least I have a wider pick of tyres. Interesting that many are going Briggies BT010 front and BT020 rear. Might be worth a try, along with some superbike school lessons to give me a confidence boost through the corners.

More acceleration down low might be the way to go. C'mon you 250 pieces of shit.
Peter Altas
BUSA-1
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#8
What revs do you do at 110km/h?
I do alot of country k's.
Peter Altas
BUSA-1
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#9
I've always considered doing the sprocket mod. 1st of all you can put a 16 tooth on the front which is similiar to changing to a 42.5 rear sprocket. This will lengthen the wheelbase which helps to keep the front down but will reduce handling a little. 2nd is what you said and put a 43 rear on. The only thing i don't like is that when the speedo reads high you will be putting more k's on the odo. Here is a link that calc's all the stuff for you.

home.cfl.rr.com/redbusa/G...index.html

Viking
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#10
Recently riding to Perth from Melbourne I clocked up the 300+ km/h mark about 9 times I counted !!!! ...Averaged one 212km section of road at 218km/h according to our clocks ...and had monos happening A LOT BETTER by the end of the trip. AWESOME !! One of the bikes was a unregulated ZX-12R, but he only managed 300 as well due to bags on back! BT-020 tyre held up brilliantly, but didn't really think of speed rating of tyre when entering warp drive!!

Felt like "Speedy Gonzalis" at times - the new cartoon guy Busa rider would know what i'm talking about!! Peter
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#11
yeah a sprocket mod is the way to go - had a 40 on the back of mine when I bought it but I also got the old one as well - changed it back to see if there was any difference and there was a very noticable decrease in thrust with the bigger sprocket so I put the smaller one back on (of course). The only con I guess would be the higher RPM at cruising speed which (from memory) went up about 500 RPM (about 4500 at 100) - I think, could be wrong (Paul whatca reckon). You also have to get a yellow box to fix the speedo.

cheers,

adrian
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#12
I'm Peter, the cartoonist is Franko (Wily E C)

...and will a yellow box fix the speedo error? How much?
Peter Altas
BUSA-1
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#13
www.blackrobotics.com/

Yellow box company.
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#14
I was referring to Paul (guy who bought my bike - Kamabusa or something )

About $200 I think for yellow box
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#15
Sounds about right Adrian, haven't really taken much notice . But I do feel it revs a little high when cruising, I kinda like it that way. I was going to ask u if you got the yellow box put in or if u bought it that way, (nifty little gadget) works well.

Needs a major service though, going to Col's shorlty (10/10th's for all you interstaters).....




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