Hello I have a Douglas engine on the engine is stamped YE6963.
Can anyone tell me how much cc it has and in what year it was build ?
YE 6963 is a 350cc side valve engine fitted to the EW model of c1926.
YE is the engine prefix for these models with the frame prefix being MF. The 600cc version of the EW from 1927-28 and the 600cc E29/F29 from 1929-1930 had an engine prefix of EH or S/EH. The later and larger 600cc models from the 1930-31 S6/T6 on were prefixed EQ for the engine and YF for the frame.