yz85 gearing

go one smaller on the front or 2 or 3 more on the back

He has displacement and a power valve you have a high reving race bke. His wil work better in that type of riding. You can do things such as gearing, flywheel weight, reeds, bore & porting, etc... but I doubt it will ever equal them out. The powervalved little KX makes great low end power for the displacement.