Hey All,
I've got an '81 and the threads in the head for the front cam chain adjuster lock bolt are stripped. I'm guessing this is a problem I can solve with a heli-coil, but I don't see a way to make that happen without pulling the head (no way to get a drill angled in there, and I'd have to pull the tensioner anyway to do it).
Any suggestions that don't involve pulling the head?
-Pete
'81 CBX
Alameda, CA
Stripped Front Cam Chain Tensioner Threads
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pbutler
- New Member & Happy To Be Here
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- Location: Alameda, CA
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sixofsix
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- Location: Verrnon, BC Canada
- Location: British Columbia
Pete:
You do not have to pull the head. The exhaust will have to come off, also the oil filter as I recall. I have done this twice over the years. You will need a heli-coil kit or two. Using a good light and getting in a comfortable position are important. First you drill it out with the drill in the kit. You will have to re-sharpen to a flatter point to get up to the bottom of the hole. Then you cut the heli-coil thread using the tap from the kit. THEN, you have to have another heli-coil tap ground down to make it a bottoming tap. Or, you can grind down the first one to make it a bottoming tap. Your choice. Now comes the sweating bullets part, you have to turn in the heli-coil, using the special tool, and then use a small drift to knock the driving tang off the bottom of the coil. And if need be, you will have to dremel off any heli-coil sticking out. If you screw up, use a hardened pick to prize out the first half thread of the helicoil, and use pliers to twist out the heli-coil and start over using you now "new" experience
. Use grease, and afterwards contact cleaner or such, to catch the swarf from the drilling and cutting. Just don't drill into the tensioner "shaft" at the bottom of the hole and take your time. Use a flashlight to inspect the bottom of the hole to confirm depth while drilling and tapping. Maybe I shortened the 2nd heli-coil with a dremel prior to installing ,after buggering up the first one, I don't remember.
Take your time and make sure the helicoil will screw in all the way before you attempt to install it. You can measure the hole depth with a vernier caliper to confirm, prior to installing.
Good Luck,
Tony
You do not have to pull the head. The exhaust will have to come off, also the oil filter as I recall. I have done this twice over the years. You will need a heli-coil kit or two. Using a good light and getting in a comfortable position are important. First you drill it out with the drill in the kit. You will have to re-sharpen to a flatter point to get up to the bottom of the hole. Then you cut the heli-coil thread using the tap from the kit. THEN, you have to have another heli-coil tap ground down to make it a bottoming tap. Or, you can grind down the first one to make it a bottoming tap. Your choice. Now comes the sweating bullets part, you have to turn in the heli-coil, using the special tool, and then use a small drift to knock the driving tang off the bottom of the coil. And if need be, you will have to dremel off any heli-coil sticking out. If you screw up, use a hardened pick to prize out the first half thread of the helicoil, and use pliers to twist out the heli-coil and start over using you now "new" experience
. Use grease, and afterwards contact cleaner or such, to catch the swarf from the drilling and cutting. Just don't drill into the tensioner "shaft" at the bottom of the hole and take your time. Use a flashlight to inspect the bottom of the hole to confirm depth while drilling and tapping. Maybe I shortened the 2nd heli-coil with a dremel prior to installing ,after buggering up the first one, I don't remember. Take your time and make sure the helicoil will screw in all the way before you attempt to install it. You can measure the hole depth with a vernier caliper to confirm, prior to installing.
Good Luck,
Tony