R75/6 swinging arm/drive shaft

[Hoff]

Just in the process of giving my R75/6 (1976) some TLC.
I am changing the drive shaft boot (old one very aged and would be cracking soon) and have a couple of questions.

1. Replacing the 4 stretch bolts connecting the drive shaft to gear box, Clymer states 22-24Nm while Haynes says 35-45 Nm
who is right? I see BMW have a special spanner but do you use it, if so where to get one?

2. Swing arm pivots, when tightening the pivot locknuts is there a special tool to hold the pivot shaft stationary while tightening the lock nut (similar to one I had for my R1200GS)?

TIA

Paul

 

[Gelandestrasse]

Don't know if you got sorted here. Short answers from me is 1. I tighten as hard as I can with a small ring spanner. I have used a torque wrench before but without the special tool, it is hit and miss for a layman. 2. there probably is. I have a turned-down socket for the nuts so I can torque them. Holding the Allen key still is an 'art' - get the right torque, find where your Allen key sits in relation to part of the frame, remove, torque nuts, check Allen key position, untorque nuts and adjust as necessary. Not as fiddly as it is written.

For longer answers see 1. https://bmwmotorcycletech.info/torquevalues.htm and 2. https://bmwmotorcycletech.info/tools.htm

 

[mikeyboy]

Flange bolts,just go as tight as you can with a normal 12 point ring spanner.
You won’t strip the threads( unless you are a gorilla)
The bolts are high tensile,into a hardened flange.
As to swinging arm trunnions.
Ensure threads are clean ,free from powder,paint etc( I run a tap through)
I centralise the arm with slip gauges,normally 3.5/4mm either side.
Then one at a time,remove the trunnion.
Loctite the trunnion,do the other,check for centralisation.torque up (v.slight preload)and leave an hour.
Then just run the lock nuts up and torque up.
I think there is a lot of Shiite quoted on this subject,
Even without the loctite I’ve never had a trunnion turn once preloaded

 

[Hoff]

Thanks for the answers.
I did just tighten the flange bolts, made sure the threads were dry. The new ones had no washers and had a red coating on looks like encapsulated red loctite ?
With reference to the swinging arm, fitted the swing arm pins made sure equal gap both sides checking with a Vernier and torqued to first torque, then released and retorqued to final setting ensuring gap was still even. I marked the position of the pin relative to the frame, torqued up the locknuts and checked pin was still in position so all well.

 

[Hoff]

Saw this on a Facebook post this morning just glad I didn't need it!!