The Dave Degens, c.1955 AJS 7R/Matchless G45 498cc Racing Motorcycle

• Built by Dave Degens using all original parts
• Raced by Dave at the Goodwood Revival in 2008
• Requires re-commissioning

The prototype of what would become the G45 first appeared at the '51 Manx Grand Prix ridden by Robin Sherry, eventually finishing 4th after a promising debut. In fact, the G45 was not an entirely new design but essentially a hybrid comprised of AJS 7R-based cycle parts and a tuned Matchless G9 roadster engine. The engine's bottom-end remained more-or-less stock G9 but above the crankcase there was a new aluminium-alloy cylinder barrel and 'head. Fuel was supplied by a single Amal TT carburettor and exhausted via short, megaphone-ended pipes.

In 1952 the prototype G45 garnered much valuable publicity, and not a little controversy, when Derek Farrant - later an AJS works rider - won the Senior Manx Grand Prix after leading from start to finish. Strictly speaking, a works prototype had no business running in an event for amateurs riding over-the-counter machines, but AMC quickly announced that a production G45 would be available for 1953. Although still based on that of the G9, the production version's engine incorporated a different camshaft, which opened the valves via roller-ended followers, and breathed via a pair of Amal GP carburettors mounted either side of a central float chamber. Claimed power output was 48bhp at 7,200rpm, increasing on later models to 54bhp at 7,400 revs.

Apart from revised valve gear and the eventual adoption of a forged crankshaft, the G45 changed little over the course of its life. Production ceased in 1957 after around 80 machines had been built, of which approximately half are believed to survive worldwide today. Before then, the works team's best result at international level with the G45 had been Rod Coleman's 2nd place in the 1954 Ulster Grand Prix.

Built using all original parts, the machine we offer is very similar to the Matchless G45 that Dave Degens raced in the 1960s. It was built using an original AJS 7R purchased at Bonhams' Stafford sale and an original G45 engine. The latter features Amal GP carburettors; lightweight valves; new big-ends and con-rods; and an upgraded oil pump and feed. The G45 was ridden by Dave at the Goodwood Revival in 2008 where he diced with Chas Mortimer on a 500 Manx Norton. Following a period of inactivity, the machine will require re-commissioning and thus is sold strictly as viewed. Included in the sale is the original AJS 7R engine ('7R/1673') and some spares. It is hoped that supporting documentation will be available at time of sale. Key not required.