After Riding hard for a couple of hours on my 400 Scrambler, the top end started to run like a dog, like it was running very rich. It was backfiring on a trailing throttle, and when I turned it off, the engine was stalling from a fast run when the throttle was lifted off.

I pulled the plug out and the ground electrode had broken off. It was broken, not burnt. The plug was new with only about 3-4 hours on it. Once the plug was in, it ran exceptionaly well again. I hope the plug ground electrode fell out the exhause port. I will have to take the head off to have a look for any damage.

Has anyone broken the tip of a plug like this? What causes it? I have a Wiseco and Cool head, as well as other mods.

 

I have a 650 Jetski that has done that twice . I have a few ideas as to why , but I won't dive into all that . If you put another plug in , and it runs , just ride it . If it does it again , post again .

 

Ride it till it breaks or stops - my sentiments exactly!