CMF sprocket carrier nut torque spec

[johnbowman]

Anyone know the torque spec for the sprocket carrier nut on a CMF bike? It's the big nut that holds the sprocket carrier on the swingarm.

I've searched and can't find it. I also looked in the manual. I'm leery of torqueing these old bolts and nuts too much. It's too hard to find replacements.

It would be really cool to have a quick reference torque spec list for common stuff. The owners manual has a few torque specs and general torque specs, but some seem pretty high.

[johnbowman]

Okay, I looked at the owners manual again when I got home from work. It lists a sprocket nut with 35 ft/lbs for torque spec. The description in the owners manual doesn't match the description in the parts manual, but I think that it is the same nut.

Does 35 ft/lbs sound right?

[Paul Danik]

Hi John,

   I don't have any of my manuals or parts books here to look at, but if I understand which nut you are talking about it is the one that needs loosened to adjust the chain along with the axle nut. I don't believe that in many years of loosening and tightening that nut I ever used a torque wrench on it, just gave a good tug on the riders wrench and never had any issues. Don't recall ever stripping the threads out or having it come loose while riding / racing.

   If a visual inspection of the threads on the nut and the corresponding threads on the sprocket carrier part look good I would just use a riders wrench and give it a good tightening, not very scientific, but it has worked for many years. I would want to see a failure of the nut or corresponding threads in the shop and not on the trail as the result could be a bit of a mess.

  I don't think those parts are rare, if you do have an issue I am pretty sure those items would be readily available. If you are working on a Sachs powered machine I would think I have those items in fair abundance if you do have an issue and would be glad to help you if needed. If you have any never seize type of product a dab on those threads might be a good idea. I always applied it to the engine mounting bolts, swingarm bolt, axles as well as any item that needed retightened as a matter of routine maintenance. As a matter of fact I used to loosen each spoke nipple and apply some on the spoke threads on new machines as part of race bike prep.

Hope this helps.
Paul

[johnbowman]

Paul,

Thanks for the detailed response. That's helpful. You are correct about which nut it is. I'm usually not that worried about torquing every nut and bolt. I just got concerned with this one because I'm having problems with rear sprocket alignment on an early Jackpiner. When I tighten it down, it goes out of alignment with the countershaft sprocket. I've tried it with the rear wheel and without.

I was beginning to think that the swingarm was bent. Finally, I tried another sprocket assembly that I had. It went on straight. I noticed that the bearings were dragging on the original sprocket. I had just changed them two rides ago. That's what caused me to question if overtightening the sprocket could cause problems. The sprocket carrier axle and bearings are fairly easy to get and cheap. The sprocket carrier, not so much.

I'm going to change the bearings when I get back home from Barber. Maybe they went bad.

Thanks for the tip on the antiseize. I've been using it on all the bikes. It sure does help with the axles and swingarm bolts.

It's a mudfest here at Barber this year. Very strange with no spectators. Hopefully, I'll hold up as well as the Jackpiner.

Once again, thanks for the advice. I really appreciate it!

John