The fully custom “Speedway Commission” by Australian workshop Purpose Built Moto (PBM) is a radical, street-legal reimagining of a professional speedway racer.
Built for a client named Jake, the project ditches the traditional “donor bike” approach in favor of a completely custom-fabricated chromoly frame designed around a specialized 500cc GM (Giuseppe Marzotto) engine.
This Custom Speedway Bike Is Truly One of a Kind
While true speedway bikes are brakeless machines built strictly for turning left on dirt ovals, PBM re-engineered the geometry with a stretched wheelbase and a bespoke braking system to make the “angry” racing DNA manageable on paved streets.
To transition the methanol-burning race engine to the road, PBM lowered the compression to 11:1 and engineered a complex external oiling system—using a Harley Panhead filter and frame-mounted cooling lines—to manage the heat and lubrication issues inherent in short-circuit motors.
The aesthetic is a masterclass in minimalist fabrication, featuring a hand-shaped “Art Deco” springer front end, an integrated speedo in the low-slung fuel tank, and a unique leaf-spring seat mount.
Finished with a hand-bent stainless exhaust and vintage B-51 Guide headlights, the result is a raw, mechanical sculpture that preserves the brutal character of a dirt-track slider while functioning as a high-end street tracker.
Sources: Pipeburn, Purpose Built Moto
