my brother has a 1995 formula sl 500 fan rotax and it goes about 115 km per hour .... that doesnt matter to us we just want to find a way to make it have a fast get up speed ...... should i clutch it? or any suggestions? thanks jake

Clutching and gearing. Remove the secondary and tighten the spring pressure to about 17-19lbs. I think stock they are 14-16 and I want to say stock setting is B2 or B3. You can change the spring also to do the same. Primary, you can change the stock spring out and put in a stiffer one so it engages a bit higher, say around 4k. Next easiest step is to get a one smaller tooth top gear in the chaincase. The stock weights, helix are pretty good on BRP's. Doing these three easy cheap things will wake the sled up on the hole shot and help it back shifter faster out of the corners. Unless you are drag racing, I wouldnt worry about changing the weights in the primary. Spring and gear should run you about $50 US, a pint of chaincase oil and about an hour of work.