Wiseco piston in a 98 ktm 300 exc.slencer was repacked.not the plug air cleaner is clean.hare scrambles soon.

Question

cylinder was ball honed.1st time rebuild.ran fine before.have good low and mid range but sputters at hi rpm.wont rev out.could reeds do that?power valve?carb was cleaned professionaly.he said try smaller jet.

Answer 1

look at the reeds first, but i dont think that its the reeds. it would run on top even if the reeds were worn out. you might want to look at the jetting, try running a little leaner.....

also it would not hurt to look at the power valve, it might not be opening all the way.....