Why is mine different from Chris Harris

[jagarra]

Maybe the best solution is to upgrade the pivot bolts to a newer style, rather than fighting that type.

[Ken in Oklahoma]

Maybe the best solution is to upgrade the pivot bolts to a newer style, rather than fighting that type.

I would second that. Used ones should be relatively available since that part would seldom be in demand. (The IBMWR want ads seem to be down right now. They have been my favorite resource.) There are the BMWMOA want ads if you are a member. And you could get lucky and find them on eBay.

In any event there are a lot of airhead frames out there and the pivot pins are in low demand. The trick is to find them.

Ken

[Major Softie]

IBMWR.org Marketplace still down. Kinda odd for the site to be working, but not the Marketplace.

[barryh]

That pivot pin is for a pre 1970 BMW.

So it is. I've just seen it on an R50 parts diagram. Not the usual parts fiche diagrams but one that shows the two holes clearly.

[Bigdownut]

Thanks everyone for your replies. I think I will replace the pivot pin and locking nut with a newer one.
Makes me wonder how a pre 1970s pivot pin got onto a 1977 R80/7?

[Rob]

Makes me wonder how a pre 1970s pivot pin got onto a 1977 R80/7?

You are new to the BMW airhead game, aren't you?

Many of the parts from bikes over the decades are interchangeable.
For instance, I don't know how far back it goes, but the crankcase mounting holes are uniform for a long, long time. At least for the twins. Don't know much about singles.

[Bigdownut]

Makes me wonder how a pre 1970s pivot pin got onto a 1977 R80/7?

You are new to the BMW airhead game, aren't you?

Yes is it that obvious ?

[Rob]

Back when I had my /2 conversion sidecar rig (that is a post-1970 engine slipped into a pre-1970 frame), I bought a special tool for adjusting those swingarm pivot pins. I have NO idea where it came from, but I remember selling some other /2 specific tools a while back. Some how, I kept this one, and I could even put my hands on it!!!



The head is 17mm across.
The pins are 10mm center-to-center
The pins look to be about 3mm in diameter.

Definitely replace them with the correct ones.

edit: AH-HA! Nathan still sells a version!
http://www.boxerworks-service.com/fabri ... pivot-tool

[Duane Ausherman]

That swing arm bearing adjuster pin is from a pre 1965 BMW. That was the year that they drilled a hole between the two pin holes for tightening or loosening. That center hole was for the grease.

Don't even begin to think that the torque on that adjusting pin is important. Just make it tight. I would estimate that the tool kit wrench couldn't easily put more than 25-30 lbs on it.

The easy answer is to remove it and drill a hole, but then you still have to use a pin wrench to deal with it. Go to my site for directions that work. The factory workshop manual is just crazy in how they tell you to do it.

There is so much misinformation on this whole issue, starting at the factory, then the BMW "gurus" added more idiocy and the very simple procedure got blown out of common sense.

OK, I will take my meds now.

•"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe." by Albert somebody or another.

[Bigdownut]

Thank you Rob and Duane.