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Airhead question.


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I inherited an '81 R100RS awhile back and, after storing it for a couple of years, I'm starting to bring it back to life. I flushed all the old brake fluid yesterday and thought I'd do an oil change next.

I'm just learning about this model so I've yet to buy any manuals. When I start searching around for oil filters I find lots of info on "oil cooler bikes" and non "oil cooler bikes".

What did they use in '81?

Also, can anyone recommend a good manual?

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Kruuuzn….I've kind of forgotten my airhead knowledge and gave my books to the guy who bought my last one.  My last one was an R100RT 1979.  It did not have an oil cooler.  Here are a couple of links that might be valuable to you.  There is a big airhead group out of California that is a wealth of knowledge and parts.  You might want to send them a note.


This is a link to an event they are having this weekend...I know you aren't in CA but this might give you a lead on how to get to them.  I've been gone from there so long I don't remember how to tap in to their info.  https://bmwnorcal.org/event-2083842


they have some really nice photos on the home page











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I do remember from my airhead days (76 R90/6) extreme caution is needed on oil filters especially /7 and oil cooler models. Some require o-rings to prevent low oil pressure. Snow bum was/is  their Dirtrider


From the airhead site...good luck. 



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The oil cooler will be right there out in front. If it’s there, it’s obvious. There are two oil filters, the Mahle OX-36 and OX-37. The longer one is for the oil cooler equipped bikes. The Mahle filters were and are the filters that BMW sold for these bikes, they just put them in a white box with a BMW logo on it.


For Airheads info, there is still no better place than the old Airheads Mail List. To subscribe, go to 


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Rinkydink….your post reminded me of that issue.  If the oring, as I remember it, it put on the wrong way it completely starves the engine of oil.  Mine had this crazy filter that was basically two filters that were held together with a metal strap.  It fit behind a little triangle cover that required me to loosen the pipes to get to it.  Memories....It held a whopping 2 quarts of oil.  I used all kings of oil in it with no issues.  The darn carb floats would get soaked up about every 3 years and would leak like crazy.  I just recently gave a guy my last filters, some carb floats, and a vacuum cap.  I still have a tail light that came off of it.  It had a small imperfection and I replaced it.

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Skywagon, my airhead was the same but the two piece filter was why I didn’t have to  loosen the pipes to change it. I used a six point box end wrench to remove the triangular cover. Had the same carb float problems only my bike held 3 quarts due to a MAC(?) deep oil pan/sump 

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