Ok-Supreme, just like many motorcycle manufacturers of the era, evolved from a cycle shop named "Humphries and Dawes Ltd." where business partners Ernie Humphries and Charles Dawes starting dabbling into the fast-growing "powered cycle" market. Creating a collection of motorcycles that went on to compete and win a number of TT races.

From 1927 onward, OK-Supreme Motors Ltd. powered on... producing a number of 250cc and 350cc J.A.P powered motorcycles. After the Second World War, OK-Supreme produced one last model, a 350cc J.A.P powered grass track racer - before closing its doors in 1946.

Given the task to restore this genuine British marque. We soon got to work, stripping the bike ready for its rebuild. Working through every component, leaving no stone unturned; 67 days later sees a fully restored, imperial true British Classic, roll out of our workshop.

With the tin-ware and frame back from the blasters; we continued to work through each and every piece, making repairs and shaping as necessary before priming with a galvanising high-zinc primer. Final preparation was undertaken before coating panels with a period style rust proofing enamel paint, for that perfect original look.

Engine

Powered by a J.A.Prestwich 250cc OHV engine. Fully rebuilt in-house with replaced and refurbished internals. Polished aluminium crankcases houses the polished crankshaft. Inside the VHT refinished barrel sees a replacement +0.40 thou piston, lightly honed cylinder, polished head and lapped valves. Original copper-plated rockers are replicated with in-house plating plants... Nickel plated external valve springs will protect the eternal valve gear from oxidation, keeping them looking tip-top for years to come!

The infamous J.A.P vertical pushrod tubes have been replaced with stainless steel alternatives, turned in-house on our lathe, with high-tolerance turned ends preventing oil leaks from the upper and lower joints. A neat feature that exceeds original factory specifications.

Built with “Extralube ZX1” lubricants throughout, which should keep this gem of an engine protected for up to 25,000 miles. From it's onboard oil tank, a Castrol XXL-40 + Extralube ZX1 mix flows through a recommissioned Pilgrim oil pump at a “Gluck” every 4-6 seconds. This oil flow will keep all internal components lubricated before the oil is burned through excess heat or combustion. The "Total loss" system.

This J.A.P transmits its power through a Burman HP 3-Speed gearbox. Fully rebuilt with new bearings, ultrasonically cleaned gear clusters and polished aluminium cases. With no oil seals in an original Burman gearbox, we needed to manufacture a “Hybrid Grease-Oil”, essentially, a thicker oil that doesn’t leak when cold and standing, yet flows and flicks when warm and running.

50% Classic Morris SAE-40 mixed 50% ZX1 SUPER GREASE creates the perfect consistency and best performance for a classic “Pre-unit” gearbox.

Burman’s dry-clutch, housed externally; is nickel plated for protection against unwanted oxidation, as are all external sprockets and shaft ends, spacers and all obsolete hardware.

Brake shoes re-lined with modern composites for improved braking. Wheels laced and trued with replacement rims, spokes and nipples, wrapped in a pair of Ensign universal 3.00 x 20" tyres. Nickel plated wheel spindles and replaced stainless CEI wheel nuts. ZX1 packed ball-bearing cones.

'Webb' suspension is renowned for their girder style front forks, featured on lots of different motorcycle manufactures throughout history. Spring compression suspension with adjustable damping, revolving around four linkages offering a smooth and comfortable ride. A considerable amount of play in these shafts had occurred from years of riding British roads… These shafts have been built up with soft chrome which offers a new hard wearing surface, grease for lubrication through external grease nipples. Friction plates offer the rider the ability to fine damping settings to cater to the riders’ weight and/or road conditions.