Anyone heli-coiled a cam shaft tensioner before?

[seestheday]

I suspect that my front cam shaft tensioner bolt is stripped on my 1981 CB750K (DOHC).

I loosen the lock nut, tighten the bolt to about 4ft pds (can't find torque specs) and then try to tighten the lock nut while keeping the bolt stationary but the bolt just started to back straight out without turning.  I'm guessing that this means it's started to strip.

Looking at the FSM (diagram on 6-0 and pic on 6-11 in DOHC manual), it looks like the bolt just threads into the head which presses on the tensioner.  I believe that I should just be able to fully remove the locknut and bolt, drill/tap/clean/install the helicoil and reinstall the tensioner bolt.

Is there something that I'm missing?

[seestheday]

I did a little research online, and apparently a timesert is a better option because there is very little aluminum to work with.  It also sounds like I'll need to pull the engine to do it right because of the angle.  I think I'll live with it until the winter when I was planning on pulling the engine anyways.

It's possible to do it without pulling the engine, but apparently it's really difficult to get the timesert in straight due to the tight angle.

I can apparently do it without removing the head, just put a little grease in the bottom to catch the filings and fish them out with a q-tip when I'm done.

[shinyribs]

Could you enlighten me on the timesert's,please? I know what a heli-coil is,but have never heard of a timesert. I would love to know what they are in case I need that option someday.

[TOOLS1]

A Timesert is a fancy Helicoil. It is a solid piece with threads on both the inside, and outside, but it is not made of spiral wire like a Helicoil. I don't know that they are any better then a helicoil. I have used both, and have found the Helicoil more user friendly. I have even used them on Chevy mains, and aluminum suspension parts on heavy duty trucks.
TOOLS

[shinyribs]

Oh,like the solid steel threaded inserts that Ford uses on the accessory holes on the 351 heads? But those are much bigger in diameter then a heli-coil. They would require a lager hole,if I am thinking about the same thing.

[TOOLS1]

Yea. Same thing.
TOOLS

[seestheday]

The argument I saw was that a timesert is better in this particular instance because there is a void 1/2 way down the hole and very little aluminum to work with.  Apparently it's easier to get a straight sealed hole if you use a timesert.

Tools, have you repaired a cam chain tensioner with a heli-coil?  I'd honestly prefer to use a heli-coil because I already have the tools necessary and would just need to buy that specific kit (unless it's the same as the valve cover thread, in which case I have everything I need).

[TOOLS1]

No I have not done hardly any work on DOHC engines. I prefer the SOHC engines. However I would not hesitate to use the helicoil. Just use some thread lock on it, to seal it.
TOOLS

[Lucky 1]

You still have not told us WHICH bolt is stripped. Is it the lock down bolt or is it the bolts holding the tensioner body to the cylinder head????

[Ray]

I had the same thing when I got my bike.  I just went to American 3/8  bolt. it works perfect.

                                                                                                    Ray

[Ray]

I almost forgot.  I had to taper the end a bit but it tightened right up. Benn two years now still holding fine.


                                   Ray