A novices new front end (non Busa)

[BLACKZOOK]

My Aprilia RS250 track bike is a great thing with only a couple of short comings, rubber brake lines, super soft suspension and a narrow 3” wide front wheel that can only run a 110 tyre which are hard to find in sticky compounds. Itâ€s a 1995 model with the Showa front end that is obviously designed for someone a lot lighter than my 100kg. The 95 front end has compression damping in one fork leg and a spring in the other. Spring preload can be adjusted on one leg and compression damping only on the other. She had weeping fork seals as well so I pulled the front end and took it to Terry Hay at Shock Treatment for new seals, heavier spring designed to support a fully grown person and gold valves. Terry called me a couple of days later to tell me that there are no parts available for this old front end and that I was better off transplanting something more modern.


I searched the forums and trolled the wrecking yards measuring hoping to use my original callipers and discs on the new front end and finally found a suitable replacement in a 2001 non radial RSV1000 Showa front end. The RSV has adjustment for compression and rebound dampening and has spring preload adjustment, on top of that aftermarket springs and gold valves are readily available

The wreckers wanted silly money so eBay was my friend and after several weeks a complete RSV front end came up complete with top and bottom triple clamps and axle but no axle spacers and no wheel. The auction ended and she was mine for $500.00 posted from Adelaide.


Searched the wreckers again and all I could find was a later model RSV front wheel 3.5” wide so I can fit a 120 tyre and not have to worry about riding off the edge of the tyre but its off a radial front end which means the hub disc carrier was 5mm too wide, oh well it was the right money for $140.00 and undamaged.


Got all the bits together and stripped the original front end off the Aprilia, the RSV steering stem is a larger diameter than the RS so down to ABC bearings to search the catalogue for taper rollers with a bore to suit the RSV shaft and bearing cup to suit the RS250 steering head. Found a top and bottom set but the bottom bearing was 2mm thinner that the original RS bearing so 2 x 1mm bearing shims would have to do to stop the lower tree hitting the steering head.

This morning I started the trial fit up, the old front end and bearings came out and new ones went in with spacer above the lower bearing. The top triple was slightly thicker and the retaining nut had a smaller step down at the bottom so I had to cut the centre out of an old bearing and grind it down to the right thickness to use as a spacer so that the top nut would bear on the centre of the top bearing and tension the whole stem.

All good tensioned up beautifully and moves nice and smooth, I trimmed the alloy steering stops on the frame by 3mm each side with a grinder and dremmel to give it a bit more steering lock which was pitiful with the RSV lower triple tree. Trail fitted the front guard and itâ€s a perfect bolt in fit!! The RSV forks are 1mm larger diameter than the RS250 so I had to mill the clamp for the steering damper and the clip-on bars to suit.






So she is all bolted up. All thatâ€s left to do is:
1. Machine the centre of my RS250 discs out by a mm or so to fit the new wheel
2. Machine the front hub down by 5mm (2.5mm each side).
3. Mill some calliper adaptors so that I can use the original RS Bremboâ€s, or I may have a lead on a set of RSV callipers for the right money, this would be much easier.
4. Measure the wheel centreline and turn up some spacers for each side of the wheel.

A mate has a lathe and a mill at work that I can use after hours so hopefully I can get it all done in the next couple of weeks, I might practice on some scrap first as I have never used a lathe or mill before!

In the end I hope to have a quality replacement adjustable front end for less than a grand and have learnt a few things along the way as I have never done this sort of thing before. Thatâ€s the beauty of a cheap track bike you can play and learn at the same time.

Canâ€t wait to get her finished and try out the new front end and resprung rear at a track day.

Next is to have a go at respraying the race glass, do my first two stroke engine rebuild and fit a set of expansion chambers. The mods are almost as much fun as the riding!

[Legend]

Good work, Bruce.

Looks like it will work out ok.

If you get stuck with machining parts etc (sounds like its under control thou!) let me know.

Leonard.

[pan]

"new front end (non Busa)"

Actually, the bike IS part Busa!

[kawasuki]

Turbo Hayabusa haa more like a turbo lawn mower.

[BLACKZOOK]

More progress.
I had to go to Collie in W.A. for work last week and while I was there I called into Wayne Patterson Ducati in Bunbury to catch up with Wayne and Todd who I used to race with, I was telling them about the conversion and they suggested I run a single disc with a brembo calliper off a 9 - - ? whatever Ducati. This calliper is apparently the ducks guts with 4 pistons and 4 brake pads. Wayne had purchased a pair of them and only used one on his twin turbo Ducati drag bike, he offered me the spare calliper at a silly mates rate price so I couldnâ€t help myself. Unfortunately he has milled 4mm off the calliper mount to get it to fit his cartridge Ohlins forks that he has internally modified to give only 25mm travel (sacrilege) and to fit his magnesium front wheel. So I will have to make up some new spacers to pack it out to the correct spacing for the disc. Still for the money I aint complaining.



Got back to Sydney yesterday and fitted up the calliper to the new wheel and front end but my RS250 discs are only 300mm dia (actually measure out at 295mm) and the pads were only sweeping the outer 2/3rds of the disc. So on the phone to the wreckers and found a RSV disc (320mm) that came off a bike that was binned with only 8 kilometres on it. Apparently the guy flipped it on a test ride. $100.00 for the disc and he threw in the front wheel spacers for free.






So at the moment the front end is finished all that needs to be done now is to mill out the RS250 clip on bars for the bigger forks, fit the new fork springs, paint the wheels and get new tyres. The whole conversion was easier than I expected given a bit of help and guidance from friends. I have an old compressor and spray gun that has been sitting in the shed for years so will have a lash at slapping some paint on the wheels myself.


Total cost so far
2002 RSV100 forks $500.00
RSV 3 1/2” front wheel $140.00
Bearings and spacers $90.00
Brembo 4 pad calliper $200.00
Disc $100.00

Still to buy
Softer front springs approx $130.00
New tyres front and back from Craig White


Hopefully the total cost will be under a grand plus tyres, not bad for a fully setup quality front end with top shelf brakes.



Iâ€m off to New Caledonia (work) for a week so hopefully have it all finished and ready for a test ride early next month. If the whole front end doesnâ€t fall off then Iâ€ll book in for the next track day to discover if one disc is enough!

[BLACKZOOK]

Well the front end is all back together, took me a heap of time with being away for work every week not really sure about the bearings I installed in the lower triple trees tho they seem to bind a bit so may have to look at other options. Possibly have to get a new stem pressed in so that I can fit off the shelf tapered rollers top and bottom.

Decided to have a go at painting for the first time all the panels were cracked and damaged as any truly good track bike should be so got into the fibreglass repairs and the bog.






Sanded her all back and hit it with undercoat, the result was shocking lumps and bumps everywhere apparently what felt smooth as a babyâ€s bum to the hand while sanding was not really the case when viewed with undercoat on. This painting thing is harder than it looks. So sand it all again then fill then sand again. Second try at undercoat then a shot of colour. Even stripped and painted the wheels.

[BLACKZOOK]

The orange is a base only and will be mostly be overlaid with red and black then the graphics go on then clear.











Im pretty happy with the result so far, not so bad for a first timer with a bunnings compressor and an old spray gun.

[BLACKZOOK]

Got some new parts for the RS couldnâ€t help myself - new Tyga chambers





And found a spare fairing on eBay that I got for a song to try a different colour scheme as you can tell I'm really enjoying the whole painting thing.







For a track bike she really spends a lot of time in bits but the mods and work done yourself is all part of the fun. Aw fuckit I'm slow around the track anyway, might as well shoot for the prettiest bike in the pits. Wonder how hard it would be to powdercoat the frame.

[ROD]

Great read Bruce keep the pics coming

[gazza414]

hey Bruce , paint it in Ducati Rosso Red....It'll look good!!!!!!!!!!

[Madmax]

Really impressive old boy.


Max

[Heidi1]

Can we call her the bumblebee?

[Pug]

Nice work, great to see the updates mate!