After this he was approached by John Humphries (the son of OK-Supreme's founder) to join the firm, and was given a job assembling the OHC engines. OK-Supreme produced short track racers with JAP engines. Les Graham, Andy McKay, and John Humphries soon became known as the Midlands trio of OK-JAP riders. In summer of 1938 they raced in the South Eastern Championships on Layhams Farm "mountain mile" grass track. Les took the 20 lap Matchless Trophy, setting a record in the process, despite never having competed on that track before.