Triumph 1927 SD 550cc 1 cyl sv



Triumph 1927 SD  550 cc side valve frame # 347776 engine #109279 CMT

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 gearbox and  26×3 beaded edge tyres.  
This SD is a well-restored example of a vintage British machine in the popular 500cc class and comes complete with pillion seat, acetylene lighting set, bulb horn and rear view mirror. 
1927 was the last year the SD was catalogued.