Spark plug hole stripped - help!

[fluke12]

1972 cl 350 stripped spark plug when I was doing plug chops. One side was always a little off and I guess I over did it. I've read a bunch of posts about it and I'm weighing options.

Do I use something like fix a thread in place and try to blow out the metal really REALLY well or pull the head and do it right? I've never opened the engine so I'm a little nervous about that. Can that be done in the frame or do I have to pull it out of the bike too?

Thanks for the advice! In the future I plan to be a little more gentle with the plugs.

 

[Moa]

Always do it right! Which means you probably have to pull the head so no crap gets inside. Fix it with a thread repair insert like helicoil, or even better, a timesert. Could be a good opportunity to give your top end a bit of a refresh.

 

[reds]

Thread insert. Set motor at TDC so valves are closed. Grease the tap so the shavings stick to grease. Shop vac out spark plug hole. Add insert. Add spark plug. Enjoy!!


* If you have a compressor you can lightly(part throttle) use a blow gun into the cylinder while holding shop vac tight above it to get any remaining pieces that may be left. This step would be AFTER initial shop vac'ing with no compressed air. AND also read LIGHT blowing of blow gun as full force can wedge pieces into places like ring rings and valves

 

[Hoosier Daddy]

One of the vintage motor cycle mags I read had a "How-To" a while back on did it with the head on, used lots of grease to catch shavings... they even stuck a strip of grease covered rag in the hole to catch the shavings, then once the tapping was done, reached in and pulled out the rag. Shavings stuck to the grease... Taa-Daa!
Here it is,
https://www.motorcycleclassics.com/mc-how-to/spark-plug-rethread.aspx

 

[fluke12]

Thanks for the advice gents. That article makes it seem less sketchy to leave it in and be really through in making sure it's clean. I had the same thought about putting something in the cylinder to catch anything, just didnt know if it was a terrible idea or not. I think I'm going to try it in place and if I get nervous about it, I'll bite the bullet and pull it all apart. I'll post again once it's done so that if I have any great insights while doing it, I can share.

 

[djelliott]

Thread insert. Set motor at TDC so valves are closed. Grease the tap so the shavings stick to grease. Shop vac out spark plug hole. Add insert. Add spark plug. Enjoy!!


* If you have a compressor you can lightly(part throttle) use a blow gun into the cylinder while holding shop vac tight above it to get any remaining pieces that may be left. This step would be AFTER initial shop vac'ing with no compressed air. AND also read LIGHT blowing of blow gun as full force can wedge pieces into places like ring rings and valves

Had to do it on my 350 and I did it exactly this way. Worked perfect.