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spark plug receiver threads messed up

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guys

need some important advice, the threads that receive the plug are screwed up, when i took out my plug it was very hard to take out, the threads near the bottom were munched

i needed to ride the bike last weekend and ended up just mashing in another plug...the bike ran fine but now the threads are mashed potatoes...

what do i do to fix this like new

thanks

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You'll probably need to pull the head and have a shop at least retap the threads. If they are really bad it will need a heli coil insert.

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Yes thats rite! Ive done heaps of these at work.

I can guarantee that a just running a tap through it wont be enough to fix it, you'll have to get it heli-coiled (new stainless screw in thread).

It is actually possible to put a heli-coil in with out taking the head off, BUT you will most likely have to take the head off because there's not enough room between where the plug go's and the bikes frame.

So just take the head to a machinist or some place like that, and it'll be done!

Good Luck! 😢

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I presume that with heli-coil being steel the bonding thing won't happen anymore ie steel plug into steel coil should be better than before?

I have used heli-coils a few times and they look quite frail but I have never had one come out!

Phillip

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guys

thanks for the info, i kinda figure heli-coil would have to be done...I'm not familiar with the kind of work...any body have it done or know how much money it will cost...

oh, and is this something any old machine shop can do? or do you really need to take it to a motorcycle machine shop

thanks

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The fact that you have a plug in there now may mean it's not as bad as you think. I'd at least try a tap before I tore it down. This used to happen to air cooled VW plug threads pretty regularly. One could use a thread chaser on it and could generally get away with this fix once, before it required helicoil. If you can keep it from galling again, you could nurse it along for quite a while. This is why I will never run a plug in an air cooled engine for long mileage without a change and always use anti seize. The guys that say they never change their plug like it's some kind of badge of honor are the poster boys for galled threads. Those dissimilar metals love to stick when subjected to all that heat. The fact that it galled may mean you were running lean or had too hot of plug for your riding.

😢

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I changed my plugs a lot, what's three bucks for a new plug?

And I still ended up mashing my threads. I tore it done and had the vavles seals redone and also had the heil-coil inserted for $75 at a local machine shop/auto race shop. They also ran it through there cleaners and all that jazz. I had the opp to clean all the carbon build up on the top of the piston too. It still is a little tough to get plugs in and out but I have never had an issue since then.

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Make sure to only put the anti-seize on the upper half of the threads on the plug (insulator side).

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gum

i'll keep that price you paid in mind when i tear it done for the work...probably around the holidays in december...what would you say, $30 to purchase and insert the heli-coil?

somewhere are here, it was either trailrider42 or thump who fabricated some guard to keep stuff from getting into the spark plug area...i'll think i'll make one while i'm doing this work

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