BMW Sport and Racing Motorcycles
BMW-Rennsport.com

Beginnings

​

Oscar Liebmann was born and raised in Jena, Germany where he followed in his fathers footsteps, completing an apprenticeship at the prestigious Carl Zeiss institute.   Shortly thereafter, in 1928 Oscar immigrated to the US.   He quickly found work at various machine shops in and around New York and New Jersey, before eventually striking out on his own. As the dust of World War II was settling, Oscar and a business partner Alfred Matzner formed AMOL Precision Corporation as a machine shop in 1946. 

 

The BMW Connection

 

Growing up, young Oscar had two passions; music and motorcycles.  With German pedigree, it was fitting that in 1950, only a few years after opening, AMOL Precision became the first official BMW dealership in the United States.  Of course there were importers who had facilitated the transfer of BMWs to the US before, but AMOL was the first official dealer, per se. As Oscar’s son Kurt tells the story, some years later BMW factory engineer and close personal friend of Oscars, Max Klankermeier, gifted to AMOL a retired pre-war Kompressor racing engine and transmission as a memento for being the first official dealership.  The choice of gift was undoubtedly not coincidental given both men’s intense passion for racing BMWs.   

 

Over the ensuing 55 years, AMOL cultivated a reputation as a superb dealership offering the latest models, and providing exemplary service.  The quality of service was no doubt enhanced by the presence of a world class machine shop situated adjacent the dealership and run by Oscar.  It’s rare, certainly today, to find a motorcycle dealership that has an associated machine shop.  It is even more rare to find a mechanical genius the likes of Oscar Liebmann. During its tenure as a motorcycle shop, AMOL retailed, serviced and raced bikes from nearly all manufacturers of the time, literally from A to Z (Adler to Zundapp!).  However the marque nearest and dearest to the Liebmanns, was and always will be BMW.  

 

Inspired

 

It was not long after the formation of the dealership that Oscar instituted a racing program at AMOL. True to the adage “what wins on Sunday, sells on Monday”, AMOL started turning out push rod race bikes in the early 50’s as the dealership prospered. Originally modifying pre-war, road going twin cam bikes, Oscar closely followed what had proved effective in Europe. Liebmann tuned the motors, converting from chain to gear driven cams, swapping battery/coil for magneto ignition and employing polished racing cranks, coupled with lightened valve trains.  Porting and polishing of heads was the norm as well.   The chassis was put on a diet and any superfluous road going gear was removed, and non-essential metal was ceremoniously shaved by means of mill, drill and lathe.  The resulting bespoke machines were then campaigned successfully around the tri-state area and Canada at venues such as Mosport, Harewood, Lime Rock, Laconia, Daytona etc.  

 

And for the well-healed racing customer, an early AMOL advertisement from November 1952 offered engine modifications such as Amal-Fischer racing carburetors, high compression pistons, racing cams and larger valves as well as racing gas tank, megaphone exhaust, racing pillion and full width hubs to complete the chassis.  

 

A new Era

 

While Oscar was busy in the late 40’s and early 50’s modifying road bikes for the track, the engineers in Munich were hard at work determining a way to re-establish BMW as a presence in international road racing. 

 

What followed in the post-war years was a design evolution, rather than revolution.  Further refinements were made to the Konigswelle boxer, over-head cam motor design.  The straight, one piece Koenigswelle or king shaft positioned horizontal and transverse to the crank was split in two.  The shafts beveled or canted downward from the case to the heads.  While the prewar Koenigswelle motor was developed as a supercharger, the post war lump was developed for normal aspiration, even though later works versions of the Rennsport were occasionally equipped with Bosch fuel injection. 

 

The first post war iteration of the new Koenigswelle race bike is now colloquially known as the Zweibolzen after the two bolts that fixed the valve cover to the head.  (The later RS54 Rennsport having 4 bolts.)  This engine and chassis proved to be the penultimate design exercise, eventually morphing into what would later be known as the type 253 or RS54.  

 

The factory race bikes, essentially early versions of the subsequent long stroke RS54 were raced as early as 1953. After modest success, BMW decided to build a small production of the long stroke racers for sale and use by a select number of privateers and development riders.  Ultimately twenty-five machines were produced, 19 in solo form and 6 sidecar outfits.  

 

One of the solo units made its way to America by way of Butler and Smith and was sold to Liebmann.  The bike was raced in the US for a short time before being shipped back to Munich in preparation for the 1959 Isle of Man road race.

 

Isle of Man

 

In 1958 Oscar Liebmann made a fateful trip to Munich.  In addition to ordering his beloved BMW 507 two-seater sports car, Oscar made arrangements for his Rennsport to receive a factory overhaul in anticipation of the upcoming racing season and in particular the 1959 Isle of Man.  The following year, the Rennsport, wearing the number 14 plate, would be piloted by Ed LaBelle to a respectable 15th place in the Formula 1 class and 20th place in the Senior TT.  Before returning the to the US, the Rennsport went back to Munich once again for further refinements and the latest upgrades, including the addition of a factory racing fairing.    

 

It was also during this trip to Munich that Oscar further developed relationships with the BMW motorcycle racing division, and in particular Max Klankermeier. Klankermeier, himself a successful sidecar racer, was a mechanical engineer and then head of the motorcycle racing division in Munich. Klankermeier was at the helm during the development of the postwar RS and is credited with overseeing its many victories by the likes of Zeller and phalanx of sidecar racers over the ensuing decades.   

 

Klankermeier and Liebmann would become lifelong friends. The men, both engineers,  shared a passion for racing and performance.  Out of this relationship was born the idea by Liebmann to further develop the RS engine making modifications and changes of his own design.  Liebmann saw untapped potential in the overhead cam design boxer layout.  He had visions of entirely reworking the motor with eye toward greater horsepower at higher RPM.  For this however, he would need parts, drawings and occasionally technical advice. 

 

Thus an arrangement was made for Liebmann to receive factory Rennsport racing parts, assistance, drawings, etc.  However there was one stipulation: the Liebmann machine, being of his own special construction, could not be raced under the “BMW” moniker. Thus the bike Liebmann envisioned would be later be known as the “OL Special”.

 

A life's work

 

In the early 1960’s, Oscar Liebmann received from BMW, among other parts, five Rennsport engine castings.  Blank canvases, if you will, for him to create his OL Special.  Realizing from past experience that the boxer engine, with the cylinders and heads protruding from the side of the bike, limited lean angle in the corners, Liebmann set about re-engineering the layout of the cylinders and heads, canting each side up by 2 degrees.  This seemingly small change would have significant reprecussions in terms of design and of course performance.  No longer a “boxer” layout, Liebmann created a “V twin”, of course not so drastic as the Moto Guzzi. To list the number of tweaks and modifications undertaken by Liebmann is beyond the scope of this article.  The end result however, was nothing short of amazing.   The OL Special was the culmination of countless evenings and weekends in his shop, over the course of nearly a decade.  The bike, after a period of working out some minor bugs, would go on to win the Canadian Road Racing Championship in 1968, as well as Daytona in 1984 and 1985.  Of note, Kurt raced the bike at the one and only Canadian Gran Prix, Mosport, 1967 against the like of Agostini and Hailwood.    It is one of the best known, and most beloved, BMW racing motorcycles in the United States. 

​

Sibling Rivalry

​

In addition to constructing the OL Special, Liebmann also used one of the five engine housings and spare parts to construct a long stroke machine.  Down on horsepower compared to the OL Special, the bike often proved more reliable and was successfully campaigned along side the OL by Fred Simone.