R51/75 History Now Complete!

The life and history of my 1950 BMW R51/75

Until recently, I only new half of the story of my R51/75.  But through a random twist of fate, and thanks to this very blog, I no longer have to imagine the early history of my motorcycle, I know it in fairly good detail.

My bike started life in Munich.  The project of Hans Bretzner (an Austrian born and German educated car designer) and a Mr. Brenner (race engine mechanic for famed German sidecar champion Walter Schneider).  The project was conceived of and begun in 1948 when Bretzner was only 18 years old.  The bike was ultimately completed in 1950.  It was constructed of new, original spare parts left over from the war.

In attempting to license the bike for road use, a 7 digit serial number was conceived, a combination of Hans's birthdate and his grandmothers house number. This proved problematic with the authorities later on as only 6 digit serial numbers were in use on BMW's at the time.  Ultimately the bike was licensed for street use in Germany and reportedly clocked 124 mph on the autobahn with the open megaphone exhaust.

Some time in the early fifties, Hans immigrated to the United States to work as a designer at GM in Detroit.  He sent for the bike in 1955, prior to which it was gone through at the BMW Works and fitted with full width hubs.

Around 1958, Hans took a job as a designer with Mitsubishi in Tokyo.  Realizing he could not take the bike with him, he reluctantly sold it to Mr. Billie Hummel.  Mr. Hummel and his wife enjoyed riding the powerful bike two up.  He proudly displayed the bike at the Detroit Auto Show, where it was well received.

In the early 60's, the bike was sold by Mr. Hummel to Dutch Becker in California.

Under Becker's stewardship the bike received new valves, specially made from Alfa Romeo racing  valves.  The work reportedly done by Taylor and Ryan Engine Rebuilding in Whittier, CA.

In the 60's, the bike traded hands from Becker to Tom Bell, who owned a gas station in Hollywood on Beverly, near La Brea.  Tom is undoubtedly the "hippie kid" who subsequently sold the bike to Duane Ausherman (some time around 1972).  Duane had run across Tom while at a motorcycle event in Visalia, CA.  Duane, then owner of BMW of Marin in the Bay Area, recognized the bike as something quite special.

One of Duane's mechanics, by the name of Art Pels, campaigned the bike at an AFM sponsored "Run what ya' brung" road race event at the Presidio in San Francisco.

The bike was purchased by Rod Miller, who in the early 1980's undertook a sympathetic restoration.  Work was limited to cosmetics and the motor was never torn down as it was always a strong runner.  Brian Hilton, mechanic for Ozzie Auer in Chico, CA fashioned new fenders for the bike.  Also added was a sportier Lugauer racing tank.

Miller later sold the bike to Bob Garrett of San Francisco.  By this time, the final drive was in need of attention.  Garrett sought out the help of legendary Bay Area machinist and mechanic Joachim Groeger.  Groeger was able to rework to final drive, but perhaps because of lack of interest or money, the bike was sold to Groeger.

It was at Groeger's shop in 2001 that I first laid eyes on the bike.  It was a wonderful machine with a large, powerful 750 motor tucked into the demure plunger frame.  When I came upon the bike, it had suffered from clutch problems. After years of persistence I struck a deal with Joachim to purchase the bike and together we rebuilt the clutch.

Later I reconditioned the top end, putting new piston rings and valves in.

I am indebted to Eric Hummel, son of second owner Billie Hummel for providing me with the photos of the bike from the late 50's and early 60's as well as filling in the information about the original owner, and builder Mr. Bretzner.

Finally, a tremendous thanks to Billie's wife, who was able to dig up the original sales ad from when her husband sold the bike in the early 60's!

The starting grid

I wonder if any of these tikes went on to have illustrious racing careers on a BMW?  I love how the kid on the inside is so serious with his tucked position, and intent stare.

BMW Roundel

The BMW Roundel is one of the most iconic brand images of all time.  The rather simple design, incorporating the company initials, has been the subject of much discussion and speculation over the years.

The Roundel has played prominently in advertising campaigns over the past 90 years, and its origins have been the subject of much discussion among enthusiasts of the marque.

For a well informed article on the history of the logo, refer to BMW Motorcycle Magazine, or this article from the New York Times.

Playing off the theme of incorporating the logo into the spinning blades of an airplane propeller, the folks at BMW recently crafted an impressive display.

BMW is the organizing sponsor of the Concorso d'Eleganza Villa d'Este in Cernobbio, Italy on the shore of Lake Como.  The event is a fantastic gathering of the most important cars and motorcycles, garnered from collections around the world.

Playing off the use of the logo in a 1929 advertisement, seen below, some crafty engineers were able to recreate the effect in real life. Click on the video for a demonstration.

Life imitating art!  The 1929 BMW advertisement comes to life at Villa d'Este.

Just so there is no confusion, the famous checkered white and blue background of the roundel was not originally meant to represent an airplane propeller.  Rather, as anyone who has visisted southern Germany will know, the white and blue colors are from the crest of the Free State of Bavaria. Despite the origins of the company in aircraft engine design, the propeller logo advertisement was not utilized until 1929, well after the roundel was created.  Nonetheless,  the logo was used in graphic design, to fantastic effect.  

See below for other advertisements prominently showcasing the famous "weiss und blau" roundel!

Spezial Kompressor

When Walter Zeller retired from racing for BMW he was given a spectacular gift.  The folks in the racing department had fabricated for him a one-off street legal kompressor.  The motor was a pre-war sidecar lump.   It was fitted to a custom tubular steel frame very similar to the RS54.  Of course the requisite headlight and taillight were included.  The story goes that Walter enjoyed the bike for several years before selling it to a school teacher who had lusted after the bike for quite some time.  After the death of the school teacher, the bike changed hands under questionnable circumstances.  It was recently sold to a dealer/collector in Germany. 

Much to my surprise, and delight, the bike was on display at the recent Veterama held at Hockenheim.  See below for some pictures.

BMW Welt



"Trick Shot" I used the panorama function on my iPhone to create this photo of BMW Welt and the Museum complex.  The buildings are actually across the street from each other.


A few years ago BMW undertook a massive project in Munich.  In addition to updating the aging BMW museum, they constructed an architectural masterpiece called BMW Welt.  A skybridge over the road connects the futuristic appearing BMW Welt structure to the iconic BMW towers and museum complex.  BMW Welt serves many functions: delivery center for owners of newly purchased BMW's, showcase for display of BMW's lineup of cars and motorcycles, showcase of BMW's boutique brands such as Mini and Rolls Royce, technology display, etc.  In addition, there a very nice restaurant and facilities for corporate events.

Across the street, the musuem appears as a round building, a bit reminiscent of the Guggenheim museum in New York.  Indeed once inside there is a spiral ramp leading visitors to the top of an impressive display.  However, this is only the tip of the proverbial iceberg.  A massive new museum complex lies partially below grade and offers visitors hours of enjoyment pouring over the impressive history of BMW, including the productions of cars, trains, motorcycles, airplane engines and jet engines.

Of course like most museums, there is a shop which sells all manner of BMW paraphernalia including an impressive number of books.  "Lifestyle" items such as clothing, toys, etc can be purchased at the BMW Welt complex.




The iconic towers of BMW.  The complex lies just north of the Olympia Park, former site of the Munich Olympics.



The museum is quite a bit larger than one might expect from looking at this photo as a great deal of it is below grade.



Inside BMW Welt



Restaurant, above which lies facilities for corporate entertaining.




The shear size of BMW Welt is difficult to capture with photos.





The original BMW Motorrad, the R32.  It is fairly well known that BMW supplied motors to various motorcycle manufacturers prior to 1923, however, the R32 represents the first all BMW production motorcycle.



"Teile in Eile" = Parts in a hurry!

My two favorite vintage BMW cars of all time, the iconic 328 and the sporty 507. 

Pre-war vertical shaft "Kompressor".  This bike was made famous by Georg "Schorsch" Meier in 1939 when he won the famous Isle of Man TT.  It was the last before World War 2, and the end of an era as the FIM subsequently banned supercharging.

Another iconic and rare pre-war race bike, the R51RS.  Similar to the road going R51 at first glance, closer inspection reveals a staggering number of differences.  Less  than 20 were made originally, and intended for accomplished privateer racers around the world.

A brief list of some differences between the R51 and R51RS include the extensive use of Elektron, a light weight magnesium alloy.  Absence of road going devices such as lights, horn, mirrors, etc.  Aluminum instead of steel fenders.  Larger carburetors.  Special cast cylinders, racing gearset in transmission, larger wheels front and rear.  Magneto ignition instead of battery/coil. Timing gears instead of timing chain.  And the list goes on...

View of the R51RS motor including the magnesium housed magneto, and the transmission support bracket that doubles as a "Kurzenhalter".



Also part of the racing display is a Rennsport in "256" Works trim.  Some of the differences from the original RS54 include a short stroke motor, larger double front brake, fairing, hydraulic brake on the rear and a rear torsion bar or "drehmoment".  The carbs are Dell'Orto and the tachometer a Smith's ATRC. 





The bike is rumored to be one that Walter Zeller campaigned.  However as far as I know most of the works bikes didn't have serial numbers per se.  And there was never any documentation about which specific bikes were campaigned at specific events.  Everyone who owns a Rennsport likes to believe that it was once owned or raced by Walter Zeller, and BMW is no different!