Need some help! I replaced the spark plug in my sons 110cc and got the plug started crooked. I didn't use a wrench, but did start it with the plug inserted into the socket and using an extension to help with the reach into the head. Now I can't get the plug started straight. Every time I start the plug, it cross threads going into the hole. Is there a tool that can be used to clean up the threads, and where can the tool be bought?

 

Spark plugs are a non standard pitch...but there are taps. The problem is that you need to pull the head off anyway or you will REALLY bugger up your motor. A new head is pretty cheap for these little Honda clones...may be the best route.

 

not a problem, you need a 10mm thread chaser, load the threads full of grease to catch the few chips and be careful, just make sure you're threading it in straight, no need to remove the head, if you screw that up then you can eaither use a heli coil or better yet, a time-sert, all without remove the head.

 

I have done this before, it's not a big deal.
Before you go out and buy the correct tap to re-cut or clean the threads.
Try using the old plug as the tool , good luck.

Joe

 

Woohoo! I got lucky! I threaded the old plug back into the hole and held pressure opposite the direction that it wanted to cross thread to and was able to "force" the plug to thread in at the proper angle. I could tell from the pressure required to turn it that it had to recut some of the damaged threads. Hopefully I won't have to change the plug for a LONG, LONG time! I'm not sure how many more times I'll be able to thread a new plug into the cylinder before I run out of luck! The plug torqued down just like it should.

 

here's a couple of pointers so it won't happen the next time,
1. always start threading in the plug with your fingers, this way you know right away if it's crossthreading
2. never remove a spark plug in a hot engine, the head is aluminium which expands more the the steel spark plug,
3. use a little antiseize lube on the spark plug threads, dissimilar materials causes electrolysis which causes corrosion