[KX500]

This is on a KX500, sorry, not the basic Shee or R, but its in a quad! HaHa. Everytime I run it past 3/4 throttle or so, and let off, the motor surges really bad, and wont go away until I put a load on the motor. Could this be an air leak or lean condition? The plug says its running rich. Very black on the porcilin, for only a few runs. Premix is 40:1. Stock motor, with 40mm Mikuni round slide carb.

 

[dajogejr]

could be lean...could be an air leak as well.

Check this thread out.

http://forums.atvdragracers.com/index.php?showtopic=4483