BMW Desmodromic Superbike

 

In the January 24 2007 edition of Australian Motorcycle News I found a curious article about a desmodromic BMW. It was under development but never raced in the superbike class for which it was intended.

The design references the “legendary Rennsport 500cc Boxer GP Engine” described in Classic Motorcycle Engines. It has a number of important differences:

• Cylinders are rotated so that the air intake is a downdraft from the top and exhaust is directly out the bottom.
• Camshafts are driven by chain rather than bevel shaft, with a secondary chain driving the inlet cam from the exhaust cam.
• The exhaust cam on the bottom of the head has been staggered slightly to give better cornering clearance. This makes the head look a bit like it has been tilted or bent in at the bottom.
• Bike is 1000cc. 

The bike was developed in the early 1990s and, apart from an outing at the Goodwood Festival of Speed in 1999, has been hidden or a museum piece.

I've uploaded a scan to https://drive.google.com/file/d/1Z_2zaSxT7sOq7AZTG9WCpb1LXAz4HwYF/view?usp=drive_link

Original was Australian Motor Cycle News, Vol 56, No 14, 24 Jan - 6 Feb 2007. Author Alan Cathcart, Photography Arnold Debus. 

Drivemag have a similar article, also by Alan Cathcart: https://riders.drivemag.com/features/bmw-boxer-r1-desmo-test-stillborn-superbike/

Desmodromology have a page on it and mention that 4 were built but only one is rideable: https://www.desmodromology.nl/bmw-r1/

Works BMW Flat Twin

The book Classic Motorcycle Engines has a chapter on the 1955 works BMW flat twin. I've uploaded it to:

https://drive.google.com/open?id=1gLaaD_xzHFQNXzSrnkPifBdrWnM_IWkg

The book was published 1986 and had detailed technical descriptions with historical context on 20 outstanding engines. In the case of the BMW chapter the engine under discussion dates from 1954, so the drawing and original discussion 1955, and the historical discussion dates 1980s. 

The technical description of the engines is incredibly dense, packing an almost unbelievable amount of information into each paragraph. I dipped into it tonight and I'm sure there was information that wasn't there yesterday. However, if you don't read it attentively you might miss things like the reference to the 500cc flat twin with desmodromic valve gear, unfortunately abandoned because of lack of funds. 

Full citation is "Classic Motor Cycle Engines: a new perspective on 20 outstanding designs", Vic Willoughby, 1986, Motor Racing Publications Ltd, Great Britain. 

Enjoy!