Question Rear Sprocket Torque Spec

Hello, I was working on the rear sprocket and “accidentally” stripped one of the stud+nut on the drive hub, I just learnt that i’m not supposed to follow the recommended spec on the Yamaha Service Manual. Question is, what is the torque spec that I should use? I don’t want to strip another one.

The manual says 72 ft/lbs. When you stripped yours, what was the setting on your torque wrench?

It was 72 ft-lbs, according to the manual, I did some research, some people also stripped theirs as well.

This might help. Randy talked about torquing in increments using a pattern. He also found the same torque specification for multiple bikes.

I think I did my last rear sprocket torque to 50' lbs.. That was 25,000 miles ago.

I believe the factory spec is too high and as you've experienced, can strip..

The stud is keeping the sprocket from spinning on the hub, the nuts (obviously),
just holding the sprocket to the hub..



Years ago, when this debate was going, I took a bolt (exact threads / diameter
as the sprocket hub) and bolted it in a vise and INTENTIONALLY checked to see
when it would strip / fail.

To my surprise, I was able to go OVER that 72 before it failed
(with a very good clicker torque wrench). I'm trying to remember, I think it was close to 90' lbs.


Being a self locking nut(s) from the factory, that alone helps a lot keeping the nut from backing off.

.


.

I believe that nut is to be torqued wet (loc-tite) so the torque value should be reduced by 10-15%, so 61-65 ft-lbs is the correct value.

Another point…most people don’t bother to calibrate their torque wrenches. All it takes is a known weight, a strap, and a vice. I use barbell weights; 5 lbs for my 1/4 drive, 25 for my 3/8 and 45 for my 1/2. Of course I weigh these and write the exact value on the weight with a sharpie.

The Yamaha manual, (S2, page 4-14) does not mention any Loctite however I agree, it certainly can't hurt.

.

Every sprocket bolt I have ever bought has been pre-coated with blue loctite. Even though this loctite is dry, it is still treated as a wet lubricant.

Gary in NJ said:

Every sprocket bolt I have ever bought has been pre-coated with blue loctite. Even though this loctite is dry, it is still treated as a wet lubricant.

Click to expand...

Interesting...

I re-used mine / never bought new Rear nuts (and don't remember if there was remnants of loctite on there).
I've never had to remove the studs..

The front sprocket, even with the little notch to push in (S2) , gets loctited on as well.

.

Currently waiting for a new stud and bolt to arrive, will reduce to 55 to 60ft-lbs this time, Thank you for the recommendation, cheers!