Now I did it!

Its me again with the Yamaha Champ (basically QT50) that wont start despite having all of the needed essentials. Now I really screwed myself and am one step closer to giving up (man I really dont want to), I stripped the threads in the head by inserting and removing over and over again and using a plug that was not intended and turned out to have different thread spacing. Now what?! Not only can I not figure out my moped mystery, i cant even try now because my compression is shot as it leaks out around the threads. Should I try the liquid thread repair used for autos, ot search for new head. And by the way prior to this i STILL cant get my other problem discovered.

Josh

Re: Now I did it!

gimmyjimmy /

josh,

You will have to remove the head and have what is called a Helicoil installed in the plug hole. (search this site for "helicoil" for more info)

Auto,motorcycle, and mower repair shops can install the helicoil for you.

Stay away from any "liquid repairs", they don't work.

another suggestion is to get another head. Always screw in the spark plug by hand until it seats, then snug with wrench.

Re: Now I did it!

Ron Brown /

I confess, I am the one who said "HELICOIL, HELICOIL, HELICOIL!!!" to Miguel, however, that was for a cylinder/head stud so maybe I can weasel out.

I recently helped my neighbor with his outboard and it's problem was that the end coil of a helicoil insert in the spark plug hole extended into the cylinder, heated up and caused pre-ignition. The other cylinder had been repaired with a one piece insert, much cleaner job and equally easy to do.

Contact auto parts, speed shops and motorcycle shops for someone with a kit.

Ron

Re: Now I did it!

Ron Brown /

Josh,

Outstanding to see someone else wrenching into the night.

Don't worry about the stripped thread, see other post.

Hang in there,

Ron

Re: Now I did it!

Brian Allen /

In lieu of a helicoil better machine shops use a swaged in fitting. Try a VW repair shop and use anti-seize compound ( sparingly and only on the threads ) on your plug and cylinder head studs.

Re: Now I did it!

Michael L. /

Ive never tried a helicoil, but the local chain shops around here (Murrays, Supertrak, etc) all have these fix-a-plug kits. i had to use one on mine. they give you a hardened steel tool that bores out the hole and taps the thread for you. you then choose the proper sized insert and put some hi-temp gasket seal around it and thread it into the hole you made. one of the threads has little teeth and you use a punch tool to expand it so the teeth grab. i had to use one and it worked great. only cost like 7 bucks for the entire kit too. The other solution (the better one) is to find someone who can tig weld and have them fill the hole (kindof a pain in the ass to do with tig) and then drill and tap a new plug hole. you can have a machine shop do it but they'd prolly charge you more than youre willing to pay.

Re: Now I did it!

Ron Brown /

Brian,

Good advice. Do you know what those inserts are called?

Ron

Re: Now I did it!

Ron Brown /

Michael,

The weld and re-tap solution is not as good as the one piece insert, as this gives you a steel thread which will not strip as easily.

Ron

Re: Now I did it!

No,but they're put in with a hydraulic....pop rivit gun would be the best description I could give you. Fun Buggies in Grand Rapids, Michigan did the ones in my VW's heads. They're neat because they won't ever pull out like a heli-coil and you can salvage heads that are too stripped out to accept a heli-coil. Al Groendyke runs the place, his phone number is 1-800-356-5571.

Re: Now I did it!

Ron Brown /

Thanks Brian.

Ron

Re:they're called..

Timeserts.

It's a self locking hardened "bushing" that grabs into the damaged threads with the outer threads, and provides a new practically strp proof threads with the ineer ones.

Jim C.

Re: Now I did it!

Chris Robertson /

I've used a system exactly like what you describe. The brand was called <i>Sav-A-Thread</i>.

Chris.

Re:they're called..

Ron Brown /

Thanks Jim

Ron

Re: Now I did it!

Ron Brown /

Thanks Chris,

Ron

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