The 500cc TRW

Designed in the 1940s for military use, Triumph’s TRW side-valver makes a great workhorse.

- Mick Duckworth

Only one twin-cylinder Triumph motorcycle produced at the old Meriden factory did not have an overhead valve engine – the 500cc TRW, made in batches from 1950 to 1964, has the side-valve configuration once preferred by military buyers. It meant fewer moving parts and easy de-cokes, while slogging reliability was required more than the snappy performance that sold Triumphs to civilians.

With a low compression ratio, the TRW has sluggish acceleration and a maximum speed of around 70mph, so it never enjoyed the admiration that has made Meriden’s ohv twins desirable classics. But it has enjoyed a niche following from military vehicle buffs, classic trials competitors and riders seeking a low-maintenance working classic. Chris Evans (no relation to the erstwhile Top Gear presenter) is one of the latter. For more than ten years he has relied on his trusty – and a bit rusty – TRW for the daily commute to work as an auto electrician. Out in all weathers, he doesn’t wash or polish his mount but applies spay-on wax to protect it from the worst of the winter.

‘I did take it up to 60mph once, but there’s no point,’ he smiles. ‘It’s quite happy up to 50 and has been very reliable in 12 years of riding.’