Triumph 1924 SD 550 cc 1 cyl sv



Triumph 1924 SD  550 cc side valve frame # 332521 engine #  94584

The SD (Spring Drive) was in fact a somewhat modernised version of the famous model H, which had grown out of the “Trusty” veteran Triumph. 
By the mid-twenties belt drive was losing its appeal to many motorcyclists, so Triumph designed a model with chain secondary drive. 
The primary chain is protected by a well-engineered aluminium case and runs in an oil bath to minimize maintenance of chain and clutch.
The powerful 550 cc engine (bore x stroke =85×97) has lots of torque. 
The machine is equipped with three speed Sturmey Archer gearbox,   26×3 beaded edge tyres, Bosch magneto  and acetylene lighting set .
This older restoration SD is an interesting example of a vintage British machine in the popular 500cc class. 
It’s a good runner.