Stripped spark plug thread

[Joshmcmillan]

So, an odd thing happened. I was riding my H-series KDX, and I had been struggling on hill climbs all day with a lack of power... the bike has also been a bit harder to start lately.
Then, towards the end of the day, the bike almost stalled, but when I pulled the clutch in it just continued to rev high, pushed the kill switch and it didn't stop, pulled the spark plug lead and it didn't stop, it just continued to rev for a while and eventually stalled.

So, what had happened, the spark plug had been lose, causing it to run lean and be low on compression (why I had no power), and it got hot enough to continue to run from pre-ignition.

The spark plug socket is stripped, which is odd as I am always very careful to not do plugs up too tight. I'd edge on the side of too loose if anything, and maybe that is what caused it? Anyway, hopefully it hasn't done any further damage and I can run a helicoil through it.

On a side note, the throttle jammed on my KX125 and threw me off flat out in 3rd gear before I thought to pull the clutch in, so I'm struggling to walk and a bit banged up, which is why I haven't properly inspected the KDX yet.

[newbbewb]

man, I have three extra heads just hanging out here, don't think they'll work on the H though. Not sure if I'd personally use a helicoil as a perma-solution. that would be a bitch if it backed out while changing a plug on the trial...

[Joshmcmillan]

I have one from an E-series too but I don't think they the same.

Next time I do a top end rebuild I plan on replacing the cylinder, so I'll just have to find one second hand that includes the head as well.

[KarlP]

You might send that head to RBD. I'm sure he can fix you up