searching for RPM

was hoping you guys would be able to help me I have a yz400f 99' stock exhaust, air box lid removed high flow air filter 48pilot 178 main needle clip in the 4th position, and air fuel mixture 2.5 turns. the problem is when I'm running at about 1/4 throttle the bike seem to be searching for an RPM it doesn't stay still. Any help that you can give me, I would be grateful for.

Maybe you have an air leak somewhere, Boit on this forum found a leak somewhere between the manifold and head on his 426, maybe you have the same problem on your 400.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now