Post WW2 - Engines identified by tag on inner chaincase

A 31A 32A 33A 34A 35A 36A 37A

C 29C 30C 31C

D 10D 11D 12D 13D

E 6E 7E 8E 9E

F 1F 2F 4F 6F 9F

H 1H 2H

K 3K

L 2L 3L

T 2T 3T 4T

Pre WW2 - Engines identified by letter stamping on crankcase

1 2 3 4 5

A 6A 7A 8A 9A 10A 14A 17A

B 6B 7B 8B 9B 10B 14B 17B

C 6C 7C 8C 12C 15C

D 9D

E 1E 2E 3E 5E

Sport Sport SuperSports   TT   Brooklands

Junior Junior JDL

Midget Midget

Can be a photo, drawing, sketch or just barrel outline
Intended as a aid to recognition for a unit unknown to you
Items here taken from Villiers material