helicoil Use

[wherearewe]

Ez guys

After doing some work under the left side cover, one of the threads partially collapsed. I use a torque wrench with a little anti-seize to 6ft/lbs so I'm not over tightening. The PO did however run a shorter 15mm bolt than the normal 22mm bolt for god knows how long in that one thread. Well that was what was installed at least when i got it. This combined with age must have strained the thread because it collapsed to that about depth, the rest is fine.

So after tapping and cleaning out the swarf i can still use the correct 22mm M6 bolt, its not ideal but it holds.

My question is, should i drill and tap the whole lot and fit a 15mm helicoil insert? Or just drill and tap to 7mm or so (the depth of the damaged area) and install a shorter 6mm helicoil? Is it likely the threads won't line up? Or should i just leave it and say 'whatever its still good' I havnt ever had much need to use helicoils to be perfectly honest.

Thanks

 

[cra-z1]

If you do decide to try and repair the thread look at a product called Time Sert.
http://www.timesert.com

 

[hard_y_rd]

Just drill and tap and use the heli-coil insert. That's what i had to do on the right side cover. The inserts are stronger than any aluminum thread. I was tempted to do more than one but let them be. As long as you can get a proper torque on them.

 

[fredintoon]

Hi wherearewe,
OK, Timeserts are stronger than Helicoils but Helicoils or even their Asian knockoffs are WAY stronger than threads tapped into aluminium.
So yeah, use whatever thread salvage insert they sell in NZ rather than hoping your thread remnant will stand up.

 

[5twins]

The short side cover screws are 25mm long so if you're using 22mm ones, even they are a bit short .....

Another worthwhile little upgrade is to swap out the original alt. cover screws for some a bit longer. The 10mm long screws Yamaha used don't reach in far enough to utilize all the threads available. Basically, it's the same scenario you've just experienced with that too short cover screw. The alt. cover is something you will remove frequently so this longer screw upgrade is highly recommended. I updated mine to stainless buttonhead Allens .....

 

[wherearewe]

Thanks guys. Will do the repair after the holidays. Have a good xmas!

 

[DogBunny]

Don't do anything. You still have enough good threads to hold a bolt. You can always go to a Recoil or a Power Coil (better Helicoil alternatives) when and if the need arises.
You should also consider which bolt is the bad one. The three that from a triangle around the clutch adjuster are the critical ones.