Old number is probably F1091...
All twins 1954-1957, including TRW500 and also 3HW, 3STriumph numbers 60-0307 or D307
Magneto advance and retard cable, length 110cm. If the magneto is fitted behind the cylinder, this will do.Made in England by DOHERTY
BSA number: 65-8714
©opyright Peter’s Classic Bike Parts