spark plug thread loose.

[flipbandit]

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i was changing my plugs today and i was suprised to see that the number 2 plug is just melted.not the whole plug. just the metal piece that the electrode was firing onto.
and my the thread on the hole is loose.
i tried to put a new plug in but its not gripping.
any ideas?

i cant put in new spark plug coz its not locking.


i wasnt able to put new plug on number 2. so i installed the melted one. and it locked. and it runs now.
but i do think i needs a re thread.
can'ti just put a weld in there fora new plug to lock? hehe

[2005B12S]

If the threads are toast, the only fix I would use is to pull the head and take it to a machine shop to be welded/rethreaded.

Don't know why the plug would be melted though. Has the bike recently overheated or suffered from excessive detonation? How many miles on it?

A dap of anti-sieze compound works wonders to prevent thread damage in applications such as this.

Good Luck, Ed.

[flipbandit]

i really don't know much bout the bike just bought it last month.
was doin a tune up. then i was surprised by it.
36000miles

[txbanditrydr]

Heli-Coil time?????

[Dave 02 1200]

I would install a Heli-Coil.  They work great and are stronger than the original threads.  

I remember that one of the standard modifications to strengthen the cases of high performance air cooled VWs was to Heli-Coil the threads for the cylinder studs so they could handle the increased loads.  

A skilled mechanic may be able to do the job without removing the head from the motor if extra care is used to vacum out the aluminum shavings that will be created when the plug hole is bored and threaded to receive the Heli-Coil insert.  

This is not the end of the world but it does make a good case for using a quality torque wrench to install spark plugs - every time.

[flipbandit]

thanx for the info.
i'm gonna ask my local mechanic if he can do something like that.

[gearset01]

Several reasons exist for stripped threads including wrong direction, overtorque, misalignment and good old fashioned corrosion, usually if youve over tightened you know it during installation. Its been my experiance that removing a plug when the engine is hot will take out threads. especially when you are talking about aluminum and steel mixed. Never Seeze is a wonderful idea. I dont think the damaged plug tip and the threads are related though. If you just bought the bike I think I would have a conversation with the seller maybe get him to " show you how to remove the plugs " tell him your not sure what you are doing and get him to do it. with you.   I'd love to be there and see that.
PIN

[Bazza]

As much as I hate dealers, I would recomend booking your bike in. A motorcycle mechanic can do a heli coil no problem at all, with the head in place, providing he can acess the hole.

It's not really a huge repair bill either. I would recomend just phoning all the dealers in your area.

[2005B12S]

The question is how are you gonna tap the hole for the helicoil without getting shaving into the cylinder. Thread grease is gonna help, but I do not see how you could do it and keep the cylinder 100% free of metal.

Metal shavings floating around and working their way into the rings is not good.

Pull the head, take it to a machine shop and have it done right. Reweld it and a fresh tap is gonna make it good as new. Might as well freshen up the top end if its needed as well.

Good Luck, Ed.

[elofdahl]

[quote="flipbandit
i wasnt able to put new plug on number 2. so i installed the melted one. and it locked. and it runs now.
 [/quote]

The old plug tightens, but a new one doesn't???  Perhaps someone has already installed an insert (helicoil or other type) and that insert has seized to the old spark plug's threads and is being retracted with the plug (I've seen it happen more than once).  If the previous owner reused it over and over again as you are doing, it could me melted (eroded) due to extremely high mileage.

[Bazza]

The question is how are you gonna tap the hole for the helicoil without getting shaving into the cylinder. Thread grease is gonna help, but I do not see how you could do it and keep the cylinder 100% free of metal.

Metal shavings floating around and working their way into the rings is not good.

Pull the head, take it to a machine shop and have it done right. Reweld it and a fresh tap is gonna make it good as new. Might as well freshen up the top end if its needed as well.

Good Luck, Ed.

Ed:

Trust me, these thread repairs are done every day in bike dealerships. It is always preferable to remove the head, but seldom is it done!

[RUSS M8]

Sounds like a good excuse to whip the head off and give it to a good tuner, clean up the ports a little, maybe up compression a tiny bit, heli coil the plug holes, and whoo hoo!  All better!

I have heard of workshops heli coiling in with the head in place, but I wouldn't do it myself.  I think I would have to remove the head.  Can't stand the thought of getting some metal stuck in the cylinder  

[Dexter]

I have spent a few years working at local shops and a Heli coil is the way to go. It is a pretty easy fix and will last longer than the original threads, all you have to do is to grease the tap for the new heli coil heavily and the grease will catch a good bit of the shavings, and after the heli coil is installed all you have to do is spin the motor over a bit with the plug out to get rid of 99% of the rest. This method has worked for me a few times on customers bikes and one of my own... hope that helps

[GSF1200S]

I have done this many times with the head in place.  To catch addtional aluminum chips that fall into the cylinder, I have used an air powered suction gun with the suction hose coated in grease.  Covering the end of the suction gun and blowing pressure into the cylinder causes the chips to fly around and get caught in the grease on the suction hose.  Keep doing this until you dont catch anymore.

  Make absolutely sure the piston in at BDC before you tap the heli coil treads.

Good Luck

Keith

[snofrog]

how do you get the tang from the helicoil out ?