Richard123vmt

As thjey come from the factory, that is? I seem to see evidence of inserts--which may have been added as repairs of course. The problem is, #4 was stripped and possibly in need of an insert. Can I successfully install an insert where one has already been installed?
In the meantime I ran a sparplug thread chaser through and brought out significant filings. After that the plug fit but I am not confident about its durability.

cbstd

No, Honda heads do not have an "insert" for the plugs. It sounds like a previous owner used an helicoil to fix a cross threaded plug. Your plug should be OK.

It is very easy to cross thread a plug into a Honda. Been there, done that.

Scott

Richard123vmt

So if there is an insert it was repaired. That's what I suspected. As of now the plug is in, but I don't know whether it is really secure. I would rather tap it and make an insert to make a secure thread--but what will happen when I try to tap on top of an insert? Maybe it will just make a mess, chewing up bits and pieces of the old insert falling out. Has anyone retapped an insert? Or is the only good repair in this situation to remove the head and have it welded, then retapped?

Ross 2.0

Time Serts are very permanent. It's not going anywhere. It's designed that way.