STRIPPED PLUG HOLE ! HELP!

[Anonymous]

I was rushing and started it in there wrong way and stripped it .. not to bad but is there any way to fix it this top end is ported and every thing...

,
John

[AOD]

is it called a helicoil? ...stabbing in the dark here.

[nert]

You can:
remove cylinder head, run thread tap from combustion side to insure using the remaining good threads as a guide and help restore the damaged threads to the way they were.

OR carefully run a tap from the outside with out removing head to restore threads.

OR if threads are damged badly, buy a repair kit that will have you drill the spark plug hole, tap it to a larger size, then thread in the provided steel insert that has the standard plug threads on the inside of the insert "bushing".

If you don't remove the head, after repair use shop vacuum to suck out debris, than crank over engine on starter with sparkplug removed to blow out remaining debris.

[Anonymous]

NERT god bless you my frined ! That helped alot I will look into some of those methods but thanks alot for takeing the time to help me!

[redliner1973]

carefully run a tap from the outside with out removing head to restore threads.
.

Just remember if you use this very acceptable method, USE GREASE ON YOUR TAP to prevent flakes from entering the chamber. :twisted:

[argonsagas]

carefully run a tap from the outside with out removing head to restore threads.
.

Just remember if you use this very acceptable method, USE GREASE ON YOUR TAP to prevent flakes from entering the chamber. :twisted:

Definitely a valid point, but after you re-thread it, use the vacuum anyway. Make an extension to fit the vacuum tubing through the plug hole (without touching the edges and stopping the air flow)and insert it to fit all the way to the piston, and let it sit there a while to suck up any debris.

[Anonymous]

okay this is turning out to be the biggest pain in the ass ... The motor is a inline 4 .. and the plug that got stripped is the inside one on the left side .. and there is not much from to work in there because frame is almost right above ... i'll try to get some pics tommorw ..

Thanks for tips,advice etc
John

[Anonymous]

PLEASE don't attempt to do this with the head still on the bike. If you have all that money in the porting and such, isn't it worth the extra work to make sure you don't get ANY metal in the engine? Do it RIGHT. Just take the head off and Helicoil it. If you don't want to spend the money on a Helicoil kit that you may never use again, any decent automotive machine shop should be able to do it for you VERY cheaply (like $25). Just take the head to them.

Be aware, though. When you Helicoil one, you have to be VERY careful from now on that the insert doesn't back out with the plug.

[argonsagas]

PLEASE don't attempt to do this with the head still on the bike. If you have all that money in the porting and such, isn't it worth the extra work to make sure you don't get ANY metal in the engine? Do it RIGHT. Just take the head off and Helicoil it. If you don't want to spend the money on a Helicoil kit that you may never use again, any decent automotive machine shop should be able to do it for you VERY cheaply (like $25). Just take the head to them.

Be aware, though. When you Helicoil one, you have to be VERY careful from now on that the insert doesn't back out with the plug.

Good advice, Mike, but I would suggest aluminum threads are not a major item, and, if they are properly cleaned from the piston area, are also not a major concern.

We are not dealing with a large amount of material, but only a tiny amount, at best.

Removing all four plugs and spinning the engine over is easy on the battery and the engine, and it will likely blow out any loose particles of broken thread, but following that with vacuuming, using a long nozzle that reaches to the piston top, should accomplish the same objective, so you may not have to remove the head.

[nert]

The small aluminum fragments you miss evacuating are not usually a problem. Actually softer than alot of the carbon that can float around inside a cylinder.
The new threads are usually cut with an interferance fit to the bushing, so the bushing remians tightly seated to the aluminum head for a secure installation and better heat transfer. You can apply Lock-Tite to the threaded insert if you want extra assurance that it will remian tight when removing a spark plug. A small dab of Never-Seize never hurt spark plug installation either.

[nabrams]

I once stripped the threads of the spark plug hole for my 1977 Honda XL350. I was really worried that it would be hell to repair.
I worried for nothing - it was easy to fix.
I got the spark plug hole repair kit from heli-coil, and now the bike runs even better than it did before (I guess it's got better compression now). I didn't have to remove the head or do any drilling. Use grease on the tapping tool.
The trick is to tap a couple of threads at a time, back the tap out, clean the chips off the tool, re-grease and then repeat this as many times as necessary. I don't think much of the chips (if any at all) fell into the head. The grease catches it all up pretty well if you frequently re-grease the tapping tool.

[AOD]

tapping is easy if you do the process right. you want to make sure you have good lubrication on the tool, and each turn you go DOWN, you should back out at least 1/2 to 3/4 a turn, then go down again. this makes sure the tool cuts are good.

~Adam

[Anonymous]

Use all the rationalizations you want, but IF a piece of aluminum gets behind or under a ring, it's going to eat the engine. It's your engine. Do what you like, but I know how I would fix it if it was mine.

If you are having trouble getting the tap in there straight, you also risk the possibility of getting the helicoil in there sideways. Again... DO IT RIGHT.