Help...stripped thread

[BarnBoy]

What the title says, clutch cover bolt stripped the threads in the right crankcase. Was stripped before I messed with it, I was using a torque wrench set to 8ft lbs. Of course it's the same hole as one of the dowel pins.

Any advice is appreciated. Hopefully I can helicoil or timesert this POS.

[El Camexican]

Have you tried running a tap through the hole yet? I find on my Yamaha’s that the factory hole is often more than 6 to 8 mm deeper than the threads are run in, so if you use a bottoming tap you can add enough threads to snug a bolt out without any additional repair.

Don’t be too worried about the fact that that hole has a dowel pin in it. The dowel pin is there to position the cover in place, and doesn’t have anything to do with adding any strength to the assembly.

You mentioned using a torque wrench on those bolts. I don’t know what kind of a torque wrench you have, but 8 mm is the smallest bolt I ever use a torque wrench on. 4,5 & 6 I judge by feel, too easy to strip aluminum with a big wrench.

[Dirtcrasher]

The reason a timesert may not be the best fix in this application is because you have a dowel pin that needs to get back in there.

Timeserts have a head, a shouldered head that stops it from going in any deeper than flush.

That's why I suggested a helicoil to you for a 6mm case bolt...

[BarnBoy]

Have you tried running a tap through the hole yet? I find on my Yamaha’s that the factory hole is often more than 6 to 8 mm deeper than the threads are run in, so if you use a bottoming tap you can add enough threads to snug a bolt out without any additional repair.

Don’t be too worried about the fact that that hole has a dowel pin in it. The dowel pin is there to position the cover in place, and doesn’t have anything to do with adding any strength to the assembly.

You mentioned using a torque wrench on those bolts. I don’t know what kind of a torque wrench you have, but 8 mm is the smallest bolt I ever use a torque wrench on. 4,5 & 6 I judge by feel, too easy to strip aluminum with a big wrench.

I haven't tried running a tap through it...that's my next step I think. It does appear like there are some threads still in there, how many and if it will be enough to hold I don't know.

Only reason I'm worried about the dowel pin is because it causes the threads to be recessed into the case.

And yes. I always thought the torque on the case bolt was like 7 or 8ft lbs. Always worked fine for me before but now I'm realizing that may be too much. I'd need a better torque wrench to go lower than than. Will likely snug by hand carefully on reinstallation.

[BarnBoy]

The reason a timesert may not be the best fix in this application is because you have a dowel pin that needs to get back in there.

Timeserts have a head, a shouldered head that stops it from going in any deeper than flush.

That's why I suggested a helicoil to you for a 6mm case bolt...

Right. I posted on the thread before I heard back from you, so I realize that now. Thanks!

Other thing I thought of was to maybe try and tap it for a M7x1.00 bolt, but that may not be any better than a helicoil.

I'll be in touch as I move forward on the repair.

[El Camexican]

Your wrist is an excellent gauge of force. It “breaks” at 9ft#. Half that is plenty for a 5mm bolt.

If you still have some thread in there you might want to try a forming tap before anything else. A forming tap does not cut threads, it forms them out of the material that is still in the hole.

Another thing I forgot to mention is that the threaded section of your hole is usually a little bit longer than the bolt that Honda put in it. This means that if for example you had a 20 mm bolt in there there’s a good chance that you would be able to get a 25 mm bolt in there.

Because this is a clutch cover you only need to snug it enough to prevent oil leaking out of the gasket.

[oldskool83]

Drill it out put in a stainless steel helical for m6 go about your life. $14 fix for a kit at hardware store. Do t ho m7 cuz the next fool who buys it will come on here asking why it's not listed on the parts list. M6 helical used about m8 od and in threaded inside for for m6. Honestly stronger then any m6 threads I to alum cases anyway.

[badasskfx]

I always go by feel on those bolts at 8ft lbs.

[BarnBoy]

Alright fellas, thanks for the responses. Just installed a helicoil tonight. Way more painless than I thought. Should be good as new now!!

[ATC King]

On small fasteners, I only use a dial type torque wrench.

Similar to this:

https://www.toolsource.com/dial-wren...s-p-90829.html

Dial type torque wrenches are some of the most accurate ones available. One reason click type are popular is because the users isn't required to look at them to get an accurate reading, which is great for inconvenient areas and angles. On a dial type, the user has to be looking directly above the dial.

The large dials either have a full 360 degree sweep, for excellent accuracy, or the measured sweep is 180 on a 360 degree dial, so the torque wrench can be used clockwise or counterclockwise. The dials are often rotatable so the needle points to zero when desired torque is reached, which makes it simpler to read instead of lining the needle up at some random point on the dial.

For motorcycle and ATV small fastener torques, a dial type torque wrench is very accurate and trustworthy. I stay away from cheap click types in that application. Click types with coil springs (the twist adjust type) are also more susceptible to getting out of adjustment and having inaccurate readings, especially if not zeroed out before storage, leaving tension on the spring.

I use a split beam torque wrench on larger stuff, and it doesn't require zeroing out before storage. There's no load on the beams when not in use, regardless of the dial setting.