2016 KOSLOW X ver TROG, by Jurassic Customs.
This Koslow was built by Shinsuke Takizawa and Toshiyuki Osawa from Tokyo, in order to race at the sand flats for the Race of Gentlemen known as TROG.
But who or what is Koslow you may ask?!!
During the late 1920’s, professional Hillclimbing began to emerge as a premier venue for American manufacturers to prove the superior performance of their machines in order to boost sales. As the saying goes, “Win on Sunday, and sell on Monday”, companies like Harley-Davidson, Indian and Excelsior specially built limited numbers of highly developed machines in order to become “King of the Hill”, which translated to much needed sales during the financial crunch of the Great Depression.
Sometime in 1928 engine-builder and tuner Andrew Koslow from Excelsior Racing Department, based the bottom-end on the high-performance Super-X Excelsior model, (which had been race proven for two years already), but modified the bore and stroke. Special, twin-port, cast-iron, overhead valve top ends were produced, with hemispherical combustion chambers, which provided for much better airflow inside the engine. Compression was out the roof at 14 to 1, and the machine burned alcohol for maximum horsepower. It is rumored that only 24 were built! At that time OHV Excelsior was America’s top Hillclimb machine and big Bertha hill climbers Gene Rhyne (Crocker future engineer), and the legendary Joe Petrali utilized the twin port hemi head configuration in a victorious way: Petrali took home the 1929 National Championship and Gene Rhyne took top honors in 1930 respectively.
When in 1931 Ignaz Schwinn, the owner of Excelsior/Henderson Motorcycle Company in Chicago, decided to shut down the business, Andy made sure that his technology was not lost, and convinced Schwinn to allow him to retain the blueprints and molds from the company’s overhead valve endeavors. Over the following years Andrew Koslow using the Excelsior top end as inspiration, would go on to produce a very limited number of specially built OHV motorcycle and midget car engines. Ever since, these special dual-port cast-iron top-ends have been known as “Koslow heads”.
Andrew Koslow ran his motorcycle shop through the 1930′s up until the early 1950′s but never built a complete bike!
