Since i have got my bike i have had nothing but trouble with the engine, spittin, sputterin and backfiring. I dont know if is a common problem but i will address it as if it was. I have messed with jets out the butt, but with no luck, untill i thought of a modification that was done on the 426. The BK mod change the engine's entire mood. It revs so quick with power that is usable and runs awesome. i am currently one up on the pilot jet and running a 170 main, needle is in stock position, and i also am running a DR. D pipe. There is a small problem with this mod on the 450 though, the hole must be drilled in the throttle cover between the bottom mounting tab and the drain hose, there is not much room there but i cleaned out a nice spot with a dremel tool which made room for my bolt. here is a website that explains the BK mod if you are not sure what it is. http://motoman393.thumpertalk.com/tech/carb.html I hope this helps someone out there. One more good tip i found is that during washing the bike water seems to find its way into every electrical connection on the bike..... solution, clean everything with contact cleaner and puchase a tube of dielectric grease and apply as needed. If there is any other tricks to this bike let me know i have been fixin everything. I got the clutch fixed with the 426 plate and shortened the engagement arm by 2mm and a hebo hydralic clutch to top it all off.
Dan
99'yz400f
03'yz450f
Dan
99'yz400f
03'yz450f