Speedway Workshop

Today in Motorcycle History


Our thanks to Ben Ludolphy who has kindly sent in details and pictures of an interesting DOHC conversion for the early Jawa-ESO 2 Valve motors

This GMT was made in 1974 by the father of Harald Mossmer, the well known builder of the HMT Iceracing-machines. The letters GMT stands for George Mossmer Trauchau.

In 1974, George Mossmer and his brother in law Herbert Kainzmeier built this conversion for the old ESO/JAWA OHV 2V engine. On the GMT there is a chain driven DOHC system for operating the 2 Valves directly by tappets. They have not built a complete new head, but instead, the camshaft housing was simply welded on the old JAWA head. Other things to note were that in this GMT engine, they fitted a JAP piston, whilst the new crankshaft (with the exception of the flywheels) was home made and the Bore x stroke were 84.5mm X 86mm.

This GMT engine was mounted into a grasstrack sidecar frame at an angle of 45 degrees, the frame itself being of a home built construction. George Mossmer, who was born 13-01-1941, was himself a very active rider from 1967 till 1976 and he custom built no less than thirteen varying grasstrack sidecar outfits.

In 19784 George used this engine in his own sidecar, but sold the engine in 1975 to Fritz Kring from Augsburg, who in turn was to use this engine for a couple of years. But the engine was to eventually return home when in 1990, he bought back the engine from another sidecar rider Edgar Moller (the uncle of iceracer Jurgen Liebman).

A most interesting motor, and one which resulted in a happy ending. Our thanks to all concerned in adding yet another rare motor to the Workshop Pages.

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