Production Model Years
1951 - 1954
Frame and Engine Numbers
522001 - 540950 / 522001 - 540950
Model Specifications
Displacement 494cc
Cylinders 2
Bore x Stroke (mm) 68 x 68
HP @ RPM 24 @ 5800
Compression Ratio 6.3:1
Valves OHV, 2 per cylinder
Clutch Dry, single plate, cable operated
Transmission 4 speed, foot shifted
Final Drive Driveshaft
Running Gear
Frame Tubular steel double cradle
Front Suspension Hydraulically damped telescopic fork
Rear Suspension Plunger
Front Brakes 200mm drum, single (1951-1952) or dual (1953-1954) leading shoe
Rear Brakes 200mm drum, single leading shoe
Ignition Magneto
Spark Plugs Bosch W240
Generator Noris 6V/L45/60 6V 45W
Capacities & Measurements
Weight 190kg
Fuel 17l
Wheelbase 1400mm
Top Speed 140kph
Number Produced 18949


Mine's a 1953 model

Darryl.Richman's picture

You can see that because of the half hub brakes but dual leading shoe front brakes. The rubber gaiters didn't come in until 1952. There are a couple of details that are the wrong year: I mounted a 1954 tail light so that I could include a rear brake light; 1954 is the first year for a brake light on a production BMW. And the transmission is from an early bike, you can tell this because it has no shroud, nor even provision for bolting on a shroud, around the Hardy disk that connects the output flange to the driveshaft.

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--Darryl Richman
"Bling is not made in Germany" --OTL, 12/05


GRBMW 1951 R51.3's picture

Hello and glad to be on the site! I currently live in Greece and work for the US Navy. I was fortunate to find a 1951 R51/3 and am currently restoring it. I will eventually head back to the states and wanted to inquire if anyone knows of mechanics that specialize in classic BMW's. My concern is with brake changes, tuning the carbs, etc. I also wondered of anyone has a maintenance schedule for the bike. I have a manual but wondered if there was an electronic one. I don't have too much time or all of my tools to do it all myself. Thanks in advance for the help and stay safe!

R51/3-68 Motorcycle Restoration and Service Manual

guest's picture

Hello GRBMW, I see you posted this in 2013, so this reply may be mute. For information on your bike, I have and would recommend purchase of the Barrington motor works manual. This is the most comprehensive manual I've ever come across, its pricy but the information it contains for the R51/3 is unmatched, easy to read and understand. Even Craig Vechoric, owner of Bench Mark Works states its the best he has seen on the R51/3. Look into it, go on their website, BARRINGTON MOTOR WORKS and check it out, if you decide to purchase it you will not be disappointed. Good luck with your restoration. Both of these people, Bench Mark Works and Barrington Motor Works do restoration work and also a good source for parts.

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