Rotax Supermoto special

The Bike

With any special there has to be some development and mine has been no exception, it started life as a 1989 RM250. I bought it as a 1 year old bike for £1500 off a friend, I paid a little over the odds but I knew this bike had been looked after very well.

I used it for around 5 years in enduroe's, MX and trail riding and then decided it needed to be butchered! In went the Rotax motor and a few years of messing around later it was back on the road in time for a holiday to Spain, another 3 years of trail riding and commuting  and I laced up the rear rim from my spare rear wheel, which was from a 125 and was slightly narrower, onto the spare front hub, believe it or not the rear spokes were perfect, fitted the worn tyres from my 86 GSXR and it was used in my first Supermoto event in November 2000 at Blyton.

For 2001

Wheels
The front rim is an Akront 2.75 X 17, this rim was one my dad bought for his Africa Twin when he tarted it up but the daft twit didn't check the amount of spokes before ordering it. Honda's use 32 spokes in the back wheels and he ordered a 36 hole rim, thanks very much dad. Its a little narrow but what the hell.

The rear rim is a 4.25 X 17 Morad, this rim is about half the thickness of the front Akront and I've managed to dent it in a pothole at Blyton.

Brakes
The 320mm front disc is laser cut from stainless steel, it helps to be an engineer sometimes. This is then fitted into a machined aluminum centre, ala PFM. This disc has lasted for a season of racing with only a little scoring so I'll be using it in 2002 but getting a spare cut. 

Picture of front disc, honest.

Front caliper is off a Fireblade and was found at a breakers in Carlisle. I took it to bits and measured the thickness of the inside end and then filed it down to around 1.5mm to clear the spokes. The caliper is operated by the standard 11mm master cylinder off the RM.

Rear brake is standard other than the disc being stainless steel.

Tyres
The first tires were inters from Dynotorque but over the year I've collected some wets and slicks. I tend to use a front wet most of the time, this is a 120/?? Michelin Pilot race wet but I do have slicks and inters for hot days.
The advantage of the wet is that it helps to grip on the gravel strewn tracks we have here.

The rear tyres are usually 160/?? or 165/??. I use a wet or inter most of the time as I like to have a lot of movement (must be the Grasstrack). The chain just rubs on the side of the tyre but it's been no problem.

For 2002

The big development, a new frame and all the extra bits that requires.
After a bit of thought over the last part of 2001 I decided to make a new frame for the "Thing" as Dave Lippet has christened it. This decision was prompted by me wanting to make the bike look a little better and for a bit of a challenge, well I got the challenge but I'll leave it up to you as to whether it looks better.

I've gone for a perimeter type frame, the two top tubes being 1 3/8", 14 gauge CFS2, the front down tube 40 X 40 box and the bottom frame tubes 1", 14 gauge CFS2. Oil tank is between the the two top and front down tubes and has a capacity of 2 Lts.
The first stage of making the jig from the old frame and then checking it for square etc was quite easy, cutting and bending the tubes, making the headstock and swinging arm pivots and then tacking and welding them together took about 3 days, making and welding on all the little bits and pieces took around another month or more of evenings.

New parts I've had to make to suit the frame.

Sub frame.
Footrest brackets.
Swinging arm bushes.
Engine plates.
Fuel tank
Miscellaneous brackets
Clean up many parts and Nickel plate them.
Tart up the engine cos I couldn't have a new frame and stick the engine back in as it was.
New 520 KTM plastics and seat
All in all about another month and a half of evenings.

As I'm writing this (28/03/02) I've still to finish the engine (just got some new parts today), paint the frame and clean up the forks and polish the wheels. Then it's time to put it all together with new cables etc.

The bike was finished in time for the NORA round at Three Sisters on the 21st April.
Filled the frame with oil, primed the pump and added some fuel to the tank, started first kick.

Wish the meeting at 3 Sisters had gone the same but in practice the throttle stuck open half way round the last turn before the start and finish straight. The problem turned out to be a small bit of the braid out of the new cable, I'd cleaned the cable out as well because I'd known this to happen before.
So first meeting, first time on the track and I'm in the tyre wall, not a good start to the year!