Topic: Head Games... Spark Plug Helicoil Replacement

[iya0yas]

I recently had a mechanic install a M12x1.25 helicoil in my CL175 Head to restore one of the two spark plug threaded holes.  Unfortunately, I recall no sealant was used during installation of the helicoil.  Now, as you can imagine, I cannot develop sufficient compression due to leakage past the helicoil threads and the spark plug crush washer OD is not large enough to seal the leak.  I'd like to know if it's possible to remove the helicoil and install a new one but this time with sealant. 

Boy it would be nice to avoid having to remove the engine from the bike and disassemble the head...again (assume machining work will be done with the piston at TDC).

Perhaps there's an alternative way to seal the existing helicoil?

Thanks-

[lucky]

I recently had a mechanic install a M12x1.25 helicoil in my CL175 Head to restore one of the two spark plug threaded holes.  Unfortunately, I recall no sealant was used during installation of the helicoil.  Now, as you can imagine, I cannot develop sufficient compression due to leakage past the helicoil threads and the spark plug crush washer OD is not large enough to seal the leak.  I'd like to know if it's possible to remove the helicoil and install a new one but this time with sealant. 

Boy it would be nice to avoid having to remove the engine from the bike and disassemble the head...again (assume machining work will be done with the piston at TDC).

Perhaps there's an alternative way to seal the existing helicoil?

Thanks-

Should have used red Locktite.

Are you sure it is leaking past 3/4 inch of threads???

[Bodi]

You can try "wicking" Loctite 290.