09/10/2026
The Weslake DOHC 500 is such a cool old-school racing engine because it looks almost agricultural, yet it was built for one thing: making serious power on the track. Developed in England from the work of Harry Weslake and Weslake Research & Development, this big single uses a DOHC four-valve cylinder head, and the tall, compact design gives it that unmistakable vintage speedway-engine look. There’s something really satisfying about seeing a competition motor this raw and mechanical.
What makes it really good is the way the two camshafts control four valves on one big cylinder, giving the engine much better breathing than a basic pushrod single. The roughly 500cc capacity, near-square bore and stroke, high-rpm capability, and methanol fuel setup were a great combination for speedway, grass track, and long-track racing, where strong torque and quick throttle response mattered more than everyday refinement. It was a serious piece of performance engineering for its time.
And the coolest part is how unique the whole thing is. One cylinder, two cams, four valves, huge torque, and methanol fuel—all in an engine that looks almost like a piece of industrial machinery. Weslake built a reputation around getting impressive airflow and performance from relatively simple racing hardware, and this DOHC version is a perfect example. No fancy electronics, no extra cylinders, just one big piston and a whole lot of clever engineering.
