Harry Martin built his own motorcycles and as advertising he went racing them as was common in those days. Hence the slogan "winning on Sunday is selling on Monday." Martin competed many times in the Isle of Mann TT and on the Brooklands race track, all race results are with these motorcycles. This with his 250cc to 1000cc mostly JAP motorcycles. Mainly with the 350cc and later with the 500cc. Martin is also the man who invented valve overlap. With the early engines, some combusted mixture always remains in the combustion chamber. Later Martin discovered that by opening the inlet valve while the exhaust valve is still open one gets a flush which eliminates old mixture in the combustion chamber and gives a better filling and stronger combustion resulting in more speed. A fact that is still standard today but was invented by Martin in the early '10s. In the search for this better filling they tried to make holes in the cylinder (ported cylinders), just above the lowest dead center, to get more gasses out. Didn't really succeed but this is something that all major brands have experimented with (including Indian and other major brands). These holes in the cylinder are very spectacular but other than lots of smoke, oil, noise and flames they don't do much. These tests originated around 1910 to 1913 approximately.

Because H. Martin was a racer, tuner and designer, he had a habit of removing the cams when he was away from his racing engines. This was his secret to driving so fast. This is still done today especially with Speedway engines. Usually when you bought a speedway engine from a racer it was without the cam. This was also with 1 of these engines. There was no cam in it but we had a good example from the other engine.

H. Martin broke several world records with his motorcycles (see photos).

The motorcycles offered here are a 600cc OHV and a 500cc OHV with ported cylinder.

Both in good working condition (see videos).

Motors are for sale in lots only!