1960 Matchless G12: Twin Without Peer

Reputation for quality

Both brothers were keen cyclists but soon transferred their passion to motorcycles. They shared the honors at the first Isle of Man TT with Norton-mounted Rem Fowler, who won the “twins” race with Matchless taking the “singles” title. Both Charlie and Harry were riding 432cc OHV JAP-powered bikes, Harry set the fastest lap — but Charlie was home in the quicker time! The Collier brothers were also frequent competitors at the newly built Brooklands banked oval circuit; all this helped build the company’s sporting image.

In the inter-war years, Matchless established a reputation for quality with a range of singles and V-twins. Ironically, their own engines started to displace JAP in several proprietary applications. JAP experienced both quality and financial issues in the mid-Thirties, and Matchless eventually supplied both the Morgan car company and Brough Superior: that the Colliers’ engines were good enough for George Brough is a singular indicator of their quality.

Two other notable Matchlesses appeared during this time. As adventurous as Edward Turner’s 1930 OHC Square Four, the Matchless engines were both narrow-angle vees: the Silver Arrow a 400cc sidevalve twin, and the Silver Hawk a 600cc OHC four. And like the Square Four, the touring Arrow and sporting Hawk both arrived at the wrong time, 1930 and ’31, when few punters had the money for expensive, high-end bikes.

Matchless soldiered on — literally — into WWII, producing what was the dispatch riders’ preferred British wartime motorcycle. The OHV single-cylinder G3/L was a powerful and relatively light machine, easily outperforming the flathead 16H Norton and M20 BSA. It also offered the benefit of the company’s new “Teledraulic” fork. And it was the 350 and 500cc singles that maintained Matchless’ sporting tradition in the immediate post-war years. And through the Fifties, the bike to beat in motocross was a 500cc Matchless “thumper.”

Twins are born

In the late 1940s, Matchless was the principal brand in the Associated Motorcycles conglomerate. But the company needed a twin-cylinder bike, like most other manufacturers to compete with Triumph’s 1938 Speed Twin. This had effectively displaced (with some exceptions) the classic British sporting single. In 1947, BSA launched its 500 Star Twin, then in late 1948, Norton, Royal Enfield and AMC all announced 500 twins. The Matchless G9 Super Clubman (and Royal Enfield’s 500 twin) differed from the rest in both having separate cylinder heads and barrels, a replaceable oil filter and pivoted fork rear suspension.

But the Matchless twin was the only one to use a center main bearing to support its nodular iron crankshaft. With the crank supported at each end by roller bearings, the center support used a plain white metal bush through which oil was fed evenly to both crankshaft big-end bearings. As well as providing oil feed, the center bearing provided lateral location for the crank.

In a period interview with The Motor Cycle, Matchless designer P.A. Walker also described how the light alloy connecting rods were of unusual design, with the studs anchored in steel “trunnions” for extra fatigue strength, and that they contained “no less than 11 times the amount of new metal required to meet the full load at 7,000rpm.” Walker predicted that, if failure occurred anywhere, it would be at the small-end eye, “but the engine would have to be run at full revolutions for about 50 years before that fatigue condition would be reached.”

Typically for the brand, the end result was a motorcycle just a little better than the competition. Though Triumph’s twin had established the basic layout, Matchless had improved on the design: internal pushrod tubes, quieter timing and valve operation, and better cooling. Just as typically, the Matchless price was higher and the G9 sold in smaller numbers than its competition. But with its swingarm rear suspension (using AMC’s own “candlestick” and later “jampot” suspension units), Teledraulic fork, sophisticated engine and Burman gearbox, the G9 was arguably the best of the new twins.

Responding a little late to the demands for more power from its U.S. distributor, AMC produced the 600cc G11 for 1956 — a full five years after Triumph’s 650 Thunderbird and BSA’s 650 Flash. (A small number of 550cc export-only G9Bs had previously been shipped to the U.S.) The capacity increase was gained by taking the bore from 66mm to 72mm, while the stroke stayed at 72.8mm. The company finally caught up in 1959 with a further stretch to 646cc by increasing stroke to 79.3mm — the G12. The CSR version was especially popular with the café racer crowd with 8.5:1 pistons and more chrome. 1960 saw a new cylinder head with increased swirl for better combustion efficiency, distinguished by two extra cooling fins under the exhaust port.

The engine had one more stretch. In 1962, a few hundred 750s were produced with the designation G15/45 (for cubic inches). Aimed at the U.S. market, the engine used revised castings, and the cylinders were not interchangeable with the smaller engines. It seems the extra power from 100 more ccs and the 10.25:1 pistons were too much for the crankshaft, too, with period reports of engines blowing up after the center main bearing failed.

AMC had owned Norton since 1953, and in 1962, the famous Bracebridge Street, Birmingham factory was closed. Norton production moved to Plumstead, and not surprisingly, an increasing number of parts were shared across the models. A “new” G15 fitted with a 750cc Norton Atlas engine, fork and hubs arrived for 1964. But AMC was already in serious financial trouble and declared bankruptcy in 1966, effectively marking the end for Matchless.

Rick Fisher’s 1960 G12 Matchless

“I just knew I wanted an older bike,” says Rick when I asked him why he bought the Matchless. Rick had recently finished restoring a Rickman Honda and a Triumph T160. “And I didn’t want to do a Bonneville,” he says.

Originally sold in Canada, the G12’s early history is unknown, but one Rod Gustafson is known to have purchased it in 1972, then sold it to Stan Verbicky, a machinist in the Naval dockyard where Rick was a Petty Officer. Rick bought the bike in 2001.

“It was a roller,” says Rick. “It had some wrong tin on it, but it was all together — sort of.”

The motor had been less than fastidiously assembled at some time in the past, so Rick entrusted it to Maurice Keeler in Seattle. Maurice took it down to the last screw and meticulously rebuilt it. He found the center main bearing shell crushed, the result of fitting an undersize shell to the standard-size crank journal. Potentially catastrophic, this would have blocked oil supply to the big-ends — a blowup waiting to happen. There were similar horrors in the top end: mild steel threaded rod had been glued into the heads in place of the correct studs, and the exhaust ports had been hobbed out to accept Sportster pipes.

Keeler dynamically balanced the bottom end and fitted 0.040-inch over 9.5:1 pistons. A high-capacity oil pump and super sports camshafts went in as well as new valves, guides and springs, and the heads clamped down with oversize bolts. Keeler also modified the oil filter, replacing the stock gauze with a replaceable element filter from a Triumph Trident, and added a 5/8-inch (ID) hose to take care of engine breathing. The result, says Rick, is a completely oil-tight engine.

“I’m sure the reason it runs so well is that it’s using filtered oil,” says Rick.

Forsaking the Prince of Darkness, Rick fitted a 220-watt 3-phase alternator, Podtronics regulator and Boyer micro-digital ignition with 40kv coils. The Boyer trigger unit is built into the original magneto housing. But getting the tinware together proved to be the most difficult task.

Because of the high-capacity oil pump, Rick needed an oil tank with a froth tower, and bought five before he got the right one. Other parts came from Richard Gaunt in England (the correct valanced front fender and stays), from the AJS/matchless Owners Club spares scheme (seat cover), from Walridge Motors in London, Ontario (shocks), and from Domiracer/Accessory Mart (sadly now extinct).

“They bought out AMC when they left North America,” says Rick. “All I needed to do was find the correct part number in my parts manual, and cross reference it.”

“When the rear carrier arrived, it was still in the AMC burlap wrapping. ”

Rick admits to becoming obsessed with getting the air cleaner right. With help from AJSMOC (AJS & Matchless Owners Club) in the Netherlands, “I built the air cleaner as an exact match of an original I borrowed from a guy in North Carolina,” says Rick. When all the parts were together, including the period hard bags Rick found on eBay, Steve Sharpe (Victoria, B.C.) completed the paintwork.

The result is a testament to what a British bike can be if properly screwed together: reliable, practical, fast and fun to ride. And it looks great, too! MC