M4GoodSamaritan and spark plug thread repair

[LabRat675]

So my triumph lost power and sounded awful one exit from home on 101 tonight. I pull over and its still running but sound like it has an exhaust leak. I shut it off and start looking for obvious signs something has broken, fallen off or otherwise; also nothing leaking. I start it up and it coughs but catches and I look down and there is blue flame out the exhaust if I blip it. So I quickly turn it off again take my helmet off and start pushing. :rolleyes After 3/4 of a mile of pushing a good samaritan pulls over and asks if I need help. He gave me a ride home so I could get my truck. If you're on here THANKS AGAIN!!! arty

Anyways, I thought that I burned a valve as I was due(overdue) for a valve check. After finding a very strange looking plug I tried to put a new one in and after some very confused screwing I come to realize that there are no threads at all. The plug blew out most likely because it had been backing out all along. I checked the valve clearance for that cylinder and they are tight but not far off. So those will be adjusted but no sign of anything at 0 clearance or broken.

What is the suggested fix? Should I take the head to a machine shop, helicoil, other? This is my daily commuter so I would like to have it back running again quickly as possible. The bike is not going to see any more track time and has 40K on it already. I'd like to see 100K so I am looking for something that will last as long as the rest of the bike will.




TL/DR: I gone and broked it. Pestering barf for the best way to repair spark plug threads

 

[auntiebling]

I'd call machine shops and see if it can be done on the bike, or maybe with just the engine dropped.

You can search here in General or the Garage for machine shop suggestions. Performance Concepts, I think, is probably the one you want

 

[seadog]

+1 for the person to stop and give you a ride.:thumbup

If it were mine, I'd pull the head and install a threaded insert, Helicoil, etc. I know people who have made this repair on car/truck engines without pulling the head but I'd be concerned about getting metal chips in the cylinder.

Also use anti-seize on the threads when installing spark plugs (may want to check the other plugs while you're there). And a torque wrench too. Many people over torque the spark plugs.

 

[afm199]

You can do an insert without pulling the head. And the metal chips are all aluminum, a chip that gets into the combustion chamber isn't going to do much damage.

Very much use a torque wrench, those plugs only get 5 ft lbs or so, just enough to crush the washer.

 

[Jalopyshoppe]

You can do an insert without pulling the head. And the metal chips are all aluminum, a chip that gets into the combustion chamber isn't going to do much damage.

Very much use a torque wrench, those plugs only get 5 ft lbs or so, just enough to crush the washer.

Thank you for saying that. I have done many repairs this way with zero issues. I use grease on my tap if I am making a cut. Catches the chips.

 

[LabRat675]

This is the first plug I have had this happen to on 7 vehicles and over quarter million miles. I always start them by hand and torque per the manufacturers instructions (different types of plugs/sizes).

I'll give the helicoil a try and if I have any issues ill send it out for a full re-work. I learned the grease trick a while ago and I've only had to use it once. It's a neat trick to know when you need it.