02 Yz250

I would imagine you could re-jet this and help it out a lot. I believe a lot of the racers run their bikes jetted as lean as possible. I woudl too, if I needen maximum performance. I dont.

The bike might not run quite as nice a bit more rich, but it woudl help to avoid race gas.

If this fails, you could lower the compression some.

I have an '02 (stock) and my bike doesn't detonate at all w/ stock jetting and pump fuel (500-2500' MSL & 70 degrees). Maybe your friend runs in sandy condions under a high load which could bring on detonation, in which case you would want to run a slightly richer main. Race fuel should not be necessary on this bike. You could also try putting the stock pipe back on which, by the way, is better than any of the aftermarket pipes out there. Good luck!!!

buy it, keep the pipe and v-force and get a couple of jets and have fun. there is no reason you cant run this bike on pump gas unlees it has had serious engine mods. even in this senario you could run a thicker gasket or have the head modded by eric for very little and be good to go!