Do you recall…
There have been some stunning motorcycles produced by the British industry, sadly way past the time when they could have been successful though.
When it was that the G85CS was launched?
The day of the archetypal competition machine from the British industry – a compete in anything/ go anywhere motorcycle – typified by the BSA Gold Star to give one example, was long gone when Matchless announced their 500cc MX machine to the press. It was a machine in true Matchless style, a separate engine and gearbox as they had used for many years, a massive frame and an overall look of a big bike. With its silver frame and an alloy tank with a red panel it screamed ‘tradition’ but the world had gone modern and even BSA had consigned their Gold Star to the history books, with their works team mounted on ultra-light four-strokes.
Lacking the massive resources of the BSA group there was little option for the owners of the Matchless marque but to use what was in the group to produce a motorcycle. This meant the non-unit construction 500cc roadster-esque machines. Thanks to Norton coming into the fold there had been a superior bottom end available for some time, there was still welding available and tubes to make frames, AMC’S Teledraulics were still a good fork, as was the front brake and there were some AJS 7R rear hubs available so the potential to lighten things and carve a few pounds off the bike was there.
It was actually a brave thing to do, launch a bike which was technically out of its time, but not a silly thing to do. Yes the main GP classes were dominated by bigger two-strokes and BSA unit singles but there was a 750cc class for big bikes and maybe there was the thinking of using the new bike – still designated G80CS at that time – for such events as these.
The new bike was announced in late 1964 and the press were told a new machine was to be built to evaluate production. Though following tradition the machine which was prototyped must have been envisaged by the Rickman Metisses being built and raced at that time, they too would have used Matchless engines. There is the puzzling thing as to why Matchless didn’t cut a deal with the Rickman brothers, but they didn’t.
The press got a hold of the latest, exciting, new Matchless scrambler early in 1965 and announced it as the first new 500 from the company since 1960. The company’s all-alloy competition engine had a slightly over square configuration with an 86mm diameter piston travelling 85.5mm up and down the barrel. Over square dimensions give a faster revving engine and while ‘faster revving’ is not generally a British thing – one can almost hear the boardroom saying “Faster revving? Oh no dear boy, we do long strokes here y’know…” – the world was changing and
There have been some unlikely motorcycles converted to off-road use but one would hesitate to take a modern 350cc road racer, bung some MX tyres on it and attempt to win a world 500cc MX championship. This was pretty much what Bill Nilsson did with his reworking of an AJS 7R for 1957. Not only did he use a road racer he increased the capacity to near 500cc before AMC did for their G50 Matchless. There were a few more tweaks the Swede did to his 7R, there’s a BSA gearbox in there and higher bars than the road racer would have and they clamp in what look like BSA yokes, and the rims are more scrambles sized, but it is still clearly a 7R. Were AMC happy and delighted with the publicity? Not exactly… though their disgruntlement didn’t prevent them claiming kudos for the inaugural world championship win of course. Bill took the bike – it was his in any case – repainted it and renamed it Crescent and carried on racing it and very nearly lifted two more titles with the bike… he would win another world championship in 1960, this time with Husqvarna colours on his bike.
in order to attempt to compete, modernity had to be embraced. This 86mm diameter piston compressed the mixture at 12:1 and this was good for 41bhp at 6200rpm which on the right gearing meant ‘road gears’ would propel the package along at close on 120mph! On lower scrambles gearing there should arguably have been enough speed to make the bike a noted performer. Coping with this performance there were some internal changes too, with a bigger main bearing on the timing side, a solid crank pin and a bigger oil pump ensuring the bike got all the lube it needed, where it needed it.
As one can imagine the fuel needed for such a compression ratio isn’t 95E5 pump fuel, oh no, it’s something a bit more traditional, something with a bit of octane in there. Perhaps the readership can be divided here into those who remember going to an ordinary petrol station and filling up with five star and those who think “what IS he on about?” Oh and Matchless slipped on an 13⁄8in GP carburettor to ensure as much fuel got in the combustion chamber as possible. Luckily, too, the old managerial edict “we don’t fit an air cleaner as they clog and spoil the fine carburation…” attitude had also gone by this time as opening the throttle wide on such a carb could well suck in all sorts of miscellaneous things.
The task of producing a bright enough spark to ignite all this fuel was down to a Lucas racing magneto… these instruments were hand fettled in Lucas’ comp shop and until electronic ignition came along they were the bee’s knees.
Behind the engine sat the AMC gearbox which was strong enough for the job and had been on the previous G80CS incarnations, though there was a change in the way the primary case was set up. Inside the pressed alloy cover was the excellent clutch with four friction plates to grip and provide drive, a single row primary chain joined gearbox and engine but instead of sitting in a bath of oil, this chain was lubed by oil mist from the engine breather.
Housing all this was a bronze welded frame made from Reynolds 531 with various diameters of 14 gauge tube used to make up the twin down tube construction. A similarly made swinging arm pivoted on Silentbloc bushes at the frame end and Girling suspension units controlled the back end. At the front were Teledraulics with a whole 5in of suspension travel. Front braking was provided by a standard 7in Matchless or AMC competition hub, it had worked well for years and just because it was the Sixties didn’t mean it would stop working, oh and there were a few in the stores too, simply machine off the cooling fins on the outside, which saved an ounce or two and lace on a 21in diameter rim and away you go.
The rear hub however, is one worthy of note… AMC had for a few years produced one of the prettiest 350cc ohc race bikes, their AJS 7R. It bristled with exotica such as funny metals weighing less than a glass of water and had a conical rear hub cast from Elektron – a trade name for a magnesium alloy popular in the aero, motor and motorcycle racing industries, as it’s light, strong and easy to cast. For the new G80CS one of these hubs, fitted with a 4.00in x 18in Dunlop rim and Dunlop MX tyre went into the swinging arm. The whole wheel and tyre was 16lb lighter than the previous model’s rear wheel. This would have contributed greatly to the all up weight saving of 100lb on the new machine over the old one.
Also helping shave the pounds off would be the alloy oil tank – fitted between the engine plates – an alloy petrol tank and alloy mudguards. Tantalisingly there was no production launch date available just the cryptic “an announcement is expected soon…” Is it being cynical to suggest having hand-built a few
“The rear hub however is one worthy of note… AMC had for a few years produced one of the prettiest 350cc ohc race bikes, their AJS 7R.”
Though AMC’S G85CS was too late on the scene to develop its true potential, there’s no denying it’s a great looking machine, but when a rider of Vic Eastwood’s calibre gets passed in a GP by riders on smaller, lighter bikes, then the big bike era must be over.
The bike in this section of our archive feature is on display at the National Motorcycle Museum – the pics are taken on the lawn at the museum – and is representative of the last of the line.
A frame which, depending on your view, was either influenced by or a direct copy of the Metisse, parts from other machines in the AMC stores and glass fibre tank certainly added up to a pretty package and had it been out a few years earlier then a much more successful life would have been realised for the bike.
To be honest, the bike produced plenty of power but the package this power had to haul was much heavier than the opposition. AMC were quite coy about the actual weight and it’s not even mentioned in the brochure but they did say to Motorcycling that the bike weighed in at 285lb on the startline.
machines for their star riders, Matchless let the press loose on one for a full write-up and gave more details than they could have been expected in the hope of gauging public demand? If it flopped in the press and the reception was mediocre perhaps the spares bins in the stores would have remained unraided.
Heading to Brands Hatch where the factory had brought their works team models to try out, Motorcycling’s man Mike Bashford claimed the new bike was triply exciting because of its newness, potential and it being the only fully built ready-togo heavyweight dirt bike available in Britain at the time. The bike which would be ridden on that day was Chris Horsfield’s factory machine and differing only in it had smoothed inlet and exhaust ports over any standard spec. Bashford was handed the reigns to this thoroughbred with a comment from Horsfield along the lines of “be careful when you open it up as things happen.”
Horsfield was 500cc Grandstand Champion and was clearly looking out for his bike. Also along on that day was Dave Nicoll whose own works bike had been assembled the night before. As might be expected the difference between the two bikes – Horsfield’s being in use through the season and Nicolls’ freshly built – meant Bashford liked the Horsfield bike best and had problems with Nicolls’ bike as the rider it was built for was 6ft 4in tall and Bashford wasn’t…
The new machine came in for praise in the handling department and there was no reason not to believe the Nicolls bike would equal the Horsfield one once through the settling in process.
By the time there was a production version of these machines the designation had become G85CS, though it was the same machine mostly… Gone was the alloy petrol tank and in its place was a red glass fibre one, also gone was the Reynolds 531 tube with chrome molybdenum, still of high quality but cheaper, going in for the frame.
However it was not to be the saviour of the company or the industry as it truly was the era of the lightweight and believe it or not many would remain unsold while the competitors’ money headed first to the Eastern Bloc and then to Japan for fast, light and reliable machines.
“...the new bike was triply exciting because of its newness, potential and it being the only fully built ready-to-go heavyweight dirt bike available in Britain at the time.”