Hello I recently pulled the sprag clutch to clean on my k100rs 1984. However upon completing the job I didn't have a torque wrench up to 140ftlb. So used one that went up to 110 and did it a bit extra on the output shaft nut. Now the o ring on the output shaft has gone. The replacement from motor bins was thinner than the original. Just wondering as I've got the bike apart. Is there a knack to stop it from giving way. Or was it the fact that it wasn't up to 140ftlb.

TheJoker wrote: However upon completing the job I didn't have a torque wrench up to 140ftlb. So used one that went up to 110 and did it a bit extra on the output shaft nut. Now the o ring on the output shaft has gone. The replacement from motor bins was thinner than the original.

Not enough squeeze can contribute to o-ring failure. Correct torque values should be used. You could also have received an incorrect part. You should confirm dimensions and part numbers with the supplier.

TheJoker wrote: However upon completing the job I didn't have a torque wrench up to 140ftlb. So used one that went up to 110 and did it a bit extra on the output shaft nut.

It isn't 140 ft/lb, but 140 Nm (which is much lower)...and that is 1st stage.
Second stage is: loosen the nut and retighten to 100 Nm.

TheJoker wrote: The replacement from motor bins was thinner than the original.

The o-ring should be 19x4 mm.

Inge K. wrote:

TheJoker wrote: However upon completing the job I didn't have a torque wrench up to 140ftlb. So used one that went up to 110 and did it a bit extra on the output shaft nut.

It isn't 140 ft/lb, but 140 Nm (which is much lower)...and that is 1st stage.
Second stage is: loosen the nut and retighten to 100 Nm.

At least you won't need a different torque wrench, Joker!

Sorry I was looking at the output shaft when writing this, I've only just started using torque settings so forgot which way around it was. It was tightened relased then tightened again obiously not enough as its leaking. This is the output shaft as you can barely see (it's a bad photo) the pot of oil below the shaft. Regarding the O ring I'm not sure if it seemed bigger (thicker) because it was flattened.

For some reason the image has rotated can't change it.