The David Plant Collection, J.A.P V-twin Veteran Re-creation Project Registration no. not registered Frame no. none Engine no. 4382 'In The Motor Cycle reports of the 1905 Stanley Show there is no mention of a JAP exhibit, although a new 6hp vee-twin engine was observed fitted to a BAT machine... In point of fact, the vee-twin was not the first of its kind to leave the works at Tottenham. The first 70x95mm 6hp engine had been made in 1904, and like the water-cooled version that followed it, it had automatic inlet valves. An early photograph in the Tottenham Museum archives shows the air-cooled version fitted into a JAP motorcycle in 1905.' - Jeff Clew, JAP The Vintage Years. For many years the dominant supplier of engines to the British motorcycle industry, JAP was founded by John Alfred Prestwich in the closing decade of the 19th Century. JAP's arrival on the scene reduced British manufacturers' reliance on Continental power units, but at first the London-based company specialised in the production of scientific instruments, John Prestwich collaborating with William Friese-Green in pioneering the development of the ciné camera, before building its first motorcycle engine around 1901. In production from 1903, JAP's first engine, a 2½hp four-stroke single featuring 'atmospheric' inlet and side exhaust valves, displaced 293cc (76x70mm bore and stroke) and produced a claimed 2.25bhp at 1,600rpm. As well as supplying existing manufacturers, JAP went into motorcycle production itself, though from 1908 the firm concentrated on engine supply alone. JAP was active in competitions right from the start, entering the ACU's 1,000-Mile Trial in 1903 and supplying the engine for Charlie Collier's winning Matchless in the inaugural Isle of Man TT of 1908. This fascinating JAP project started with the basic v-twin engine, David says this may have come from the same source as the early Matchless in his collection but cannot remember. The idea was to create a JAP motorcycle of the 1904-1905 era using a photograph in a book but with variations as dictated by the components available, at no point to be an authentic copy. The frame is all new as are the engine mounts; the bottom bracket and its components; front fork bracing and yokes; inlet manifold; control levers and mountings; pedal cranks; mudguards (packed separately); exhaust box, etc. All the above were scratch built with some artistic licence. The engine is loosely assembled, the pistons, crankshaft and connecting rods being packed separately. The engine has received little attention apart from the provision of an ignition pack plate. The rear hub is new-old-stock BSA with a back pedalling brake, modified with larger spoke flanges. The front hub is believed new, again scratch built. A rear hub has now been obtained (since the catalogue photography was completed). A potentially most rewarding project. Condition and completeness unknown, Prospective purchasers should satisfy themselves with regard to this motorcycle's completeness, history, authenticity, originality and mechanical condition prior to bidding. Footnotes: BUYER'S PREMIUM The Buyer's Premium for this Lot is 28%+VAT on the first £40k of the Hammer Price, then 27%+VAT up to £800k, then 21%+VAT up to £4.5M and 14.5%+VAT thereafter. All lots are sold 'as is/where is' and Bidders must satisfy themselves as to the provenance, condition, age, completeness and originality prior to bidding. CONDITIONS OF SALE, AUCTION INFORMATION & GUIDE FOR BUYERS Please see the 'CONDITIONS OF SALE, AUCTION INFORMATION & GUIDE FOR BUYERS' at the top of the main sale page (Motorcycles Online - The Summer Sale) for all pertinent information regarding bidder's obligations, viewing, bidding, payment, post-sale collection & transportation. REQUEST A TRANSPORT QUOTE To request a UK or European Motorcycle shipping quote visit Moving Motorcycles. To request an International Motorcycle shipping quote visit Shippio. To request a Memorabilia and Spares shipping quote visit Mail Boxes Etc - Milton Keynes. Lot to be sold without reserve. For further information on this lot please visit Bonhams.com For further information about this lot please visit the lot listing
Description
Buyer's Premium
32%
Estimate £1,500-£3,000
Current Price (1 bid)
£10
Jun 05, 2026 7:00 AM EDTMilton Keynes, UNITED KINGDOM, United Kingdom
£36,000
(4 bids)£7,500

























