compression leak

[xxjeanxx30]

so i have bought a quad (1985 suzuki LT250E) and the quad had the wrong spark plug and was not tight enough I now have dirty tread and a compression leak what would be my best option try to force the spark plug or take a tap and clean the tread ?

[jen]

be carefull cleaning and chasing treads as the debris will be in the cylinder.

[Gwbarm]

If the thread is stripped you can try a tap the same size as the correct spark plug thread to try to get it to cut threads good enough to hold the plug, as a last resort you can get a heliocoil kit to create new threads. I prefer trying the tap even if the threads are partially gone there should be enough left to hold the plug and go down far enough to seal.

[Mech]

If the plug that was in there had short threads then the bottom few threads in the head have probably filled up with carbon. You should try cleaning them with a tap, and then crank the engine over a few times to blow the carbon dust you've loosened out. Hopefully that's all that's needed.

If the threads have stripped you can get a thread insert that will wind in and make it possible to use the correct spark-plug again. And as before, if you fit an insert, crank the engine over to blow any metal or carbon out. 

I've done both jobs and never needed to pull the engine apart.