Triumph - Twins 1950 - 1960

Engine Number.            Engine Number.              

Unit 350&500cc           Pre unit 500 & 650cc

Engine and frame numbers on these models were all the same and were preceded by the model code. The N suffix was used in 1950 and NA for 1951-1952. 350-500 twins all used and H prefix. The 650 models with the duplex used a D prefix and unit 650 deplex used a DU prefix. Additional suffixes were used to designate model type or condition e.g TT ( model type), C (high compression or P (police). Some of these only appeared in certain markets