Stripped spark plug threads

[Vloukole]

Hi guys

I bought a xs400 and realized that the threads of the right side spark plug was stripped. The PO re-tapped the hole and made an insert(not heli coil). Now the threads are stripped and I am sure that air is leaking from the plug. How do I fix that or prevent the air from escaping? Loctite?

 

[Yamaguy55]

Loctite won't hold: Loctite can be removed/loosened by heat.
There's a product called a Time-Sert (spelling?) that is similar to a hell-coil, but is actually a threaded sleeve with a stop to control depth, plus when you install it, the interior expands so it won't back out. Go to their website and get one for a 14mm plug, .75 inch depth.
http://www.timesert.com/html/gm.html

If it is stripped past this, maybe a machine shop can make you a special insert, or pull the head and have it welded/retapped, or get another head.

There's several people parting out here, and Brenda seems to have plenty of properly priced stuff here:
http://www.bikeboneyard.com/78%20xs-400.html

Good luck.

 

[Vloukole]

Thank you. Will give it a go.