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The early ten rapper engines were supercharged, not turbos. Then they changed the rules and outlawed superchargers after WW11. Charles

chasbmw wrote:The early ten rapper engines were supercharged, not turbos. Then they changed the rules and outlawed superchargers after WW11. Charles

Holy Crap! We've had 11 World Wars?????

Man, my history knowledge is SO behind...

Major Softie wrote:

chasbmw wrote:The early ten rapper engines were supercharged, not turbos. Then they changed the rules and outlawed superchargers after WW11. Charles

Holy Crap! We've had 11 World Wars?????

Man, my history knowledge is SO behind...

It's the US educational system that I blame.

Garnet wrote:

mattcfish wrote: A few things could be updated, but I guess the question is, why didn't this sort of design go into production? Seems to be way ahead of it's time.

There where several English bikes with bevel drive OHC, the Norton Inter (Manx) be the most famous. Ducati did it all through the 60s and 70s but had problems at high revs.

Bevel drive is VERY expensive to build and re-build as there are many close tollerances that must be met.

Yeah, but this was pre-war! Maybe the fact that Germany lost the war (WWII) , set them back on inovative designs for awhile.
I could see how pulling and reinstalling the heads could be complicated by the requirement for precise bevel gear lash.

mattcfish wrote:What sort of power did these put out compared to stock engines of the time?

According to Mick Walker in "BMW the Racing Story", Georg Meier's 500cc 1939 Kompressor Racer had 80bhp at 8,000 rpm with a top speed of 140mph (225kph) To give an idea of what a nice bit of kit it was, a R66 of 1938-41 had 597cc, but only 30bhp at 5,300rpm with a top speed of 90mph (145kph)!

mattcfish wrote: I could see how pulling and reinstalling the heads could be complicated by the requirement for precise bevel gear lash.

Base gaskets, head gaskets, and the need for precision gear alignment? Yep, that would be tough. Today, you'd make the base gaskets O-rings, but the head gaskets would still be tough.

What a great thread - thanks for all the pics too.

Has anyone ever read what I believe to be one of the best books ever written in English about the history of BMW motorcycles? Its called "Bahnstormer" by the legendary motoring journalist L.J.K.Setright.

R1 Project 1989-1992
R1-reserch / design team: Georg Emmersberger (Desmodromics), Heinz Hege, Ralf Lewien
Specs:
Performance: 135 -140 Hp (100 - 103 KW). max rpm 11.000
Engine: 4-stroke two-cyl. boxer engine, liquid cooled. Four valves per cyl. DOHC DESMODROMIC
Bore-stroke: 98 x 66 mm. 996 ccm.
Bosch Fuelinjection; electronic ignition, 6 gear, cardan.
Dry weight 165 kg.

From the R1 till 1992 only 4 prototypes were made. One of them is ridable.

Intake/exhaust similarities to this...next years R1300GS engine. Maybe not a lot else.