Triumph 1923 “SD” 550 cc side valve single frame # 327594 engine # 86265 TRI
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 TRI assembly code refers to January 1923.
Some new features for 1923 were a new type of front mudguard without the typical flare and Triumph manufactured Druid-style side-spring forks.
The machine is virtually complete in all major respect. Missing are: front hub, luggage rack, throttle and ignition levers, fuel and oil lines and other small odds and ends. What you see on the photos is what you get!
This promising project comes with sales catalogue and ( handy!) copy of parts list.
There are no documents with this vintage Triumph.
For detailed information on this model consult Peter Cornelius’ “The Facts” booklet, surf to http://users.actrix.co.nz/cornelius/Triumph/