Crossthreaded sparkplug / General engine question

[Anonymous]

I recently started bringing an old gs850g back from the dead (with the help of this site, thanks). I am now trying to get the air/gas mixture screws so that they don't foul. Here is the problem, two years ago I was also trying to get the bike going(which was succesful for the season). I call a mechanic friend, a guy who has changed automatic cars into standard... He crossthreads a sparkplug screw. Now I just jam the thing in there as far as it can go trying to use a good groove but I am unsure wether it is sealed. Four of the plugs were dark black except the one with the crossthreaded plug this plug was a little white/blue looks like something is going on. I don't know what.
p.s.

[argonsagas]

You need to be a little clearer in your descriptions......dark black is redundant, but if it is all black , how can it be white/blue?

I must presume what I saw in a store a few days ago is also available in the States.

What I saw was a kit that has a steel tap, with a tee handle, and several steel thread inserts of various lengths/depths to suit your plug/head needs. The package stated it was for use in exactly the conditions you describe.

Apparently you chase existing threads, then screw the steel thread insert right into the aluminum wall of the head, thus creating a new and lasting thread.

Does anyone have experience with these?

[Anonymous]

Sounds like it isnt sealed, it's suckin air in through the hole. The best thing you can do is go get a helicoil kit (14mm?) and install a helicoil. It could cause engine failure if it runs lean, you can burn a hole in the piston, and burn valves. Also, you dont wanna launch a plug goin down the road... it could create a divot in your leg, or physical damage to your bike, or another vehicle.

A helicoil kit provides a drill bit, tap, and steel inserts. you drill the hole out, tap the hole for the outside threads of the insert, install the insert with the included installer, (best if you use a little locktite I hear) and then thread in the spark plug and you're done.

[Anonymous]

I believe what your talking about his a heli coil............ and they can be found in the states and for a reasonable price.. The one i got a year ago, came with the drill and tap needed . I got a old honday 350 that had the spark plug stirped out. It would blow the sparkplug right out. SO i bought one of these heli coils that fit the sparkplug threads. I Cheated and stuff a rag into hole. then drilled and tapped the hole for the heli coil. They have thread locker i belive to hold it in as wel. IT worked great, but I dont recommend it. the way i did it. YOu should pull the head off so as to not get any shavings down in with the piston. BUt i dindt care about this bike it was a free toy to me.

THe issue you maybe having from sounds of it is the spark plug is not in as far as it normally would be? And i would geuss its not going to ignite the same if the position of the spark is changed.... maybe it dont matter....


but The heli coils do work great..

P.S. gsbuilder posted a nicer shorter version while i was typing lol

[argonsagas]

Agreed. It sounds the same. I have heard of the name helicoil for years, but never actually encountered it.

The package I saw had no nationally-known name on it...just the brand name the store uses.

Not certain of the price, but I think it was about $15.00 + tax, so it seemed like a fair idea.

[redliner1973]

If your not planning on a head job anytime soon, a helicoil will do the trick just fine. the store brand is probably made by Helicoil, and should suffice. I have used them successfully in Air-cooled VW's many times over, but if you ever do remove the head, have the shop weld over and re-tap a new spark plug thread. :twisted:

[SqDancerLynn1]

One word to help when drilling and tapping coat your drill bit and tap with grease, go slow and clean often. Will keep most if not all chips out of the engine