Vintage BMW Motorcycle Owners

Back in the day, before AMOL Racing switched to a RS54 platform (which they built themselves), they used various R50 pushrod motors, with shorten strokes, widened bores, etc. They also used roller rockers. This seems like a pretty elementary performance (and reliability) improvement to the valve train.

Likewise I know that San Jose BMW use to offer Roller rocker conversions to later airheads...but has anyone offered, or do they still offer roller rocker conversions for /2?

Interesting post, I was hoping for some replies,especially on the AMOL built RS54.

I kinda get the feeling that most on the board are interested in stock restorations, and not so much in racing or performance modifications. I'm quite sure that AMOL made their own roller rockers. Their machine shop was something to see. To be clear AMOL produced many racers, push-rod as well as DOHC.

Look in the attached article on page 77 you can see and read about the Roller Rockers


AMOL Article

For me, I figure my 70 MPH is just as fast as the next persons 70 MPH. So it take me 5 sec. longer to get there.
And not sure it would be worth the price one has to pay for such an up grade.


twocams

Thanks for posting the Amol article,very interesting. I wonder how many of the OL Specials are accounted for?

I know of at least one push-rod R50 that was shipped to Australia in the late 90's and another pushrod R69s that resides locally. This one is quite unique. No gaskets. All the parts fit together with interference fit for better heat transfer.

The rest are anyone's guess. I am sure the RS54s have found their way into someone's collection. Even the magnesium engine blocks alone would be worth a lot to a vintage racer.

I should add that once I was in the attic of their machine shop and there was a pre-war compressor engine just sitting gathering dust. Purchased from race salvage in Europe, although I don't know if it was ever campaigned on this side of the Atlantic.

Back to your original question about roller rockers for the street, I think it's a classic case of a solution in search of a problem. The stock valve train is very reliable. Just my HO.

Dave

Maybe I should have been clearer in the first post. I am really talking about racing performance, not improving reliability. There have been a number of successful BMW racers over the years, many transplanting R50S mills into /5 frames for a high revving, light handling combination. However, unlike with /5/6/7 engines, there seems to be only limited performance improvements available in the day (Bowman flywheels, and 750 conversions)...and of course no roller rockers which seems to be an obvious one.

I think you hit it on the head with your 2/15 post. Probably not a lot of "racing performance" interest here. Not that it's not interesting, I love reading about AMOL and their racing program... but keeping the bikes running and as original as possible seems to be the flavor on this site.

I have a friend who worked at AMOL for many years and think/thought he was a member here. I'll give him a call tomorrow and tell him to check in at this thread. He may be able to answer some of your questions as he just recently got back into Vintage BMW's (r69S).

I bought my first and only brand-new BMW at AMOL in 1984, an r80. They sold Honda too. Big loss to the BMW community when they closed.

First a little context. The original long stroke RS54 did not use a roller rocker, but rather had a rubbing block that ran against the cam lobe. It was of of a different hardened material than the body of the rocker itself and was slide in place by means of a dove tail, and then peened.

Later on with further motor development and coinciding with the emergence of short stroke 253.2 version of the RS54, there was utilization of a roller on the cam end of the "kipphebel".

Oscar Liebmann of AMOL, as is pretty well known and discussed in the above article, built a short run of AMOL Specials in the 1960's, with continued development of the bike until his death in early 80's. Two bikes were completed. They differed from the original factory RS54 by having the cylinders and heads canted up 2 degrees from the horizontal. This necessitated innumerable changes to the motor, to accommodate. The discussion of which is beyond the scope of this post.

Attached is a drawing by Liebmann for the rockers on the AMOL Special.