Basis: The legendary Kawasaki KH 250
For his extraordinary creation, Whitelock drew on the Kawasaki KH 250, which is widely used in the UK. Its air-cooled inline three-cylinder engine has a displacement of 249 cm³ in the original and delivers 26 hp (19 kW) at 7,000 rpm. The typical performance characteristics of a two-stroke engine and the low weight of 160 kg (about 353 lbs) made the KH 250 one of the brand’s best-known models in the 1970s.
Technical features of the seven-cylinder engine
For the KH 606, Whitelock combined the engine parts of six Kawasaki KH 250 engines and, together with Chris Appelbee, developed an inline seven-cylinder engine. With a displacement of approximately 83 cm³ per cylinder, this results in a total capacity of approximately 581 cm³, with the model name “606” indicating a slight bore increase and oversized pistons. The peak power is estimated at at least 60 hp (44 kW), although specific values for the crankshaft configuration and ignition intervals are not available.
For power transmission, Whitelock had to use the clutch from a larger Kawasaki KH 500, as the standard clutch of the KH 250 could not withstand the loads.
Sevenfold setup: carburetors, spark plugs, and exhausts
Seven separate carburetors were used to supply the seven-cylinder engine, as were seven spark plugs. The alternator required for ignition was pragmatically sourced from an automobile. The exhaust system with seven exhaust pipes—three on the left and four on the right—is also a custom design.
Modified frame and chassis
Since the seven-cylinder engine requires more space, the original steel tube frame of the KH 250 had to be widened. The same applies to the seat and tank, which were also made around ten centimeters wider. Parts of the chassis were taken from the larger KH 500 – including the front fork with double disc brake and the rear drum brake.
The resulting weight of the KH 606 is just over 200 kg (about 441 lbs) – making it relatively light despite the extensive conversion.
Not just for show, but fully roadworthy
Whitelock always emphasized that the KH 606 was not just a show bike, but a roadworthy motorcycle. The machine is loud, fast, and fully functional. Compared to the base KH 250, it is heavier, but still within a range that allows for sporty performance.
One-time auction in Japan
After completion in England, the KH 606 was initially operated with British registration, later with American registration. The unique piece is currently located in Japan, where it is being offered via an online auction on Yahoo Auctions Japan and buyee.jp. The auction ends on July 21, 2025. Interested parties must expect additional costs for transport and possible further fees (import/customs).
The origin of the project: Whitelock’s “crazy” Kawasaki projects
Simon Whitelock has made a name for himself in the scene with numerous extravagant custom builds. His projects range from upgrading the KH 250 to four cylinders, to the W9 design with three triple engines in a W configuration, to the famous “Tinker Toy” with 48 cylinders, which sold in 2024 for around €106,000 (approx. US$115,000).
The KH 606 is considered by experts to be a unique example of British motorcycle craftsmanship and is likely to continue to be a topic of conversation – regardless of whose collection it ends up in in the future.
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