1953 EMC 125cc Racer courtesy of Bonhams
According to the Bonhams' description, EMC was founded by Dr. Josef Ehrlich, an Austrian engineer, who emigrated to Great Britain in 1946. His unconventional ideas appear to have forced him out of mainstream production and into racing. His initial design of a phasing piston was considered a form of supercharging and was blocked from competition by the FIM. Dr. Ehrlich then built a series of Puch-based split single racers in 1952 which I believe is pictured above. Very popular in the 1953 TT with Surtees being the most notable rider. Unfortunately, he was injured on a practice run. According to the Bonhams' description, these bikes had the honor of being the noisiest bikes of all time.
Credit to Bonhams for all the info and photo