My 89 kx 125 has always had this problem, even after a new top end, lower end, seems jetted fine and it runs great. However, If I run it hard and shut it down, then restart it the plug will foul. Not totally, just enough to make the bike bog on low end and it wont clear up. even if I run WFO. Replace the plug, and it runs fine. It doesnt do this as often if I give the bike a easy cool down lap before shutting it off. I'm running one range hotter plug, and I've tried different ranges and brands of plugs.
Any Ideas ??
Thanks
Any Ideas ??
Thanks