03' YZ450F Jetting

I have a 03' YZ450F that is stock with the exception of a FMF Factory 4 slip-on. Does anyone have any recommendations as far as jetting goes. It has been around 65 degrees here and at close to sea level. It tends to backfire right after you chop the throttle on a long straight. I think it's a little lean. I think it's the pilot but I just switched to a 4-stroke and am confused.


Turn the fuel screw out 1/2 turn or so . No more that 3 turns

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