BMW R90/6 Update

For most of the last year my 1976 BMW R90/6 has been neglected.  Sadly the R90 has sat inoperable before starting the teardown this weekend.  A year ago the V Star’s pickup coil and clutch decided to go out and a week after that the BMW’s clutch cratered also.  During a ride home the lever got very stiff and on the last hard pull it made a loud expensive sounding CLANK and the lever went slack, riding in rush hr traffic on a 34 year old bike with sucky antiquated brakes at best and no clutch is not a fun experience.   I decided to fix the cheapest one with readily available parts first then its been one thing after another and before you know it wow has it been a year already?

I had been able to temporarily fix the clutch by readjusting the cables and the push rod bolts at the back of the transmission but that resulted in lots of squeaking and the clutch then being stuck open.  I’ve guessed after reading numerious threads on that the needle pushrod/throw out bearing is toast and mine sounded bad enough that I’d want to check the clutch too for damage and piece of mind.

Main thing preventing repair has been the center stand that was broken when I bought it.  I didnt have the equipment to fix it and didn’t trust any of the dealers who couldnt even find the air cleaner in the computer to lay a hand on it.  A few months ago a buddy and former BMW airhead mechanic opened a independent shop 2 miles from my house and to throw a little business his way I had him drill and retap the frame to finally repair the center stand.  With that finally done teardown can begin!

First thing was getting rid of the battery box to see what I was working with to pull the transmission.  What a royal pain in the ass that was!  In hind sight its better to leave it there and first remove the air box to give a big hole to pull it out through the side of the frame instead of out the top.   Also 4 of the 5 rubber mounts came apart and sadly I cant find any OEM replacements.  I have a link for some rubber mount fasteners somewhere that I’ll put up on my Airhead resources page I’m also working on as I rebuild it.


Next, loosening the drive shaft bolts at the back of the transmission.  The 10mm wrench in the tool kit is perfect for this, my own box end wrench was too thick to fit.   Step down on the rear brake to prevent the shaft from turning and getting these out is a snap, Cece did all of them.   You must use a 12 point box end though, these are not hex head bolts.

To remove the swingarm on an airhead you need to remove a thin recessed nut inside a tube. Its placed in such a way that a regular off the shelf socket will not fit.  You’ll need something like this special machined down and faced socket available from Northwoods Airheads.   These are very high quality and nicely made and also much cheaper than the BMW made tool for the same job that I happened to find in the stock tool kit after I started and didnt realize I had.

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