2013 YZ250F runs poorly mid RPM

At mid RPM machine misfires badly (feels a little like its at the rev limiter) - difficult to push through to a higher RPM.  Spark plug is black.  We run pilot jets one step richer than stock and aftermarket adjustable fuel screws.

 

Steps taken - leaned out the needle jet to no avail and returned to stock.  Recently discovered the condition worsens with heat and replaced the stator - also did not help.  Swapped the ignition brain and coil from another machine - also no help.  We are at the limit of expertise on this one.  HELP!

 

Raise the needle 1 clip.

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