1960 Matchless 650cc G12 CSR, Frame no. A72512 Engine no. 60G12CSRX2046

1960 Matchless 650cc G12 CSR
Frame no. A72512
Engine no. 60G12CSRX2046
As often was the case with British twins that started life displacing 500cc, the push to field a 650-class version was initiated by Americans, in AMC's case their Los Angeles-based importer Frank Cooper. The company's well-regarded singles could fend very well for themselves but Cooper wanted even more power for the twins – now overbored to 593cc – to keep buyers from migrating to competing showrooms. That boost came in 1958 with the G12 Matchless and Model 31 AJS, displacing 646cc via a longer stroke, available in standard tune and higher-rated CSR trim, the latter with raised compression ratio, higher-performance cams and a 2-into-1 siamesed exhaust setup. A bonafide "Ton Up" machine, a G12CSR on test with the U.K.'s Motor Cycling magazine posted a 108.5mph top speed.

According to the brochure, the CSR moniker stood for Competition Sports Road, though wags insisted upon "Coffee Shop Racer." Certainly the sporting model's performance credibility was done no harm in 1960 when a factory-backed CSR won the prestigious Thruxton 500-mile endurance road race for production-based machines.

This particular matching-numbers G12CSR was acquired from a Canadian collection, only the second owner of the bike. Well cared for, it was ridden regularly and entered in at least one concours, where it took a best-in-class trophy. Due no doubt to Canada's short riding season, the Matchless had logged less than 10,000 miles when it was sold to a California enthusiast in 2014. In the ensuing years, a new pattern alloy rear fender was fitted, wheel rims and sundry brightwork was rechromed, and a solid-state ignition was installed. It is sold with a letter of authenticity from the Matchless & AJS Owners Club, various correspondence and historical photographs.