The Matchless G9 is a British motorcycle made by Associated Motorcycles at the former Matchless works in Plumstead, London. The G9 was finally discontinued when the 646 cc Matchless G12 (and AJS Model 31 replaced it in the autumn of 1958.
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Showing posts with label Matchless. Show all posts
Showing posts with label Matchless. Show all posts
1957 Matchless G11
The G11 was a development of AMC's 500cc twin; in late 1955 the Matchless G9 was stretched to produced the G11, while its counterpart AJS Model 20 became a Model 30. The new 600s shared a 593cc engine (72 x 72.8mm) running 7.5:1 compression, which output around 33bhp at 6800rpm.The 600s were something of a stop-gap model, replaced three years later in the AMC line-up by the 650 Model 31 and G12. As a result, the G11 is normally over-shadowed by its larger counterpart and many folk dismiss it. 'They were interim machine that do not fall into recognised capacity limits and do not fit our accepted thinking' is how one buyer's guide dealt with the 600s.
However, these days the affordable and reliable 600s shouldn't be discounted - FW reckons they're 'very pleasant to ride, with a generous spread of power and a distinctive style. They sound good, too. The 600 engine is fairly unstressed, proving little quicker but more flexible than its smaller stablemate.' When new, a G11 would reach just under the ton, and the tweaked sports version was the first sports-roadster bike to travel 100 miles around MIRA's test track within one hour. So, even 50 years later, a G11 should prove to be an entertaining ride for travellers in Provence.
The CBP G11 had indeed been rebuilt but it was suffering from a major crankcase oil leak. Much cross-Channel correspondence ensued, with Steve the Toaster shuttling parts down to Provence and helping to wield spanners, while FW provided advice and the chaps at AMC Classic Spares came up with the correct spare parts. It transpired that when the engine was last re-assembled someone had left out a critical gasket - that never helps if you're aiming for an oil-tight engine!
With the work complete, Neil could take the G11 for a shake-down ride - this was a moment of truth indeed because he'd not ridden a Matchless before, and he wanted to be sure that the bike was suitable for his holidaymaking customers.
'I had the first ride out -- some 25 miles cruising along at 40 to 55mph,' reported Neil immediately after the ride. 'This is the first time in two years the bike has been ridden and she ran beautifully. Lots of 'firsts' here as it was the first time I had ridden a Matchless… and my first impressions were very favourable. This is a machine which epitomises what classic motorcycling with CBP is all about. A relaxed riding speed, comfortable seating position, nice burble to the exhaust without being obtrusive, easy starter... and a great looking machine to boot!
'I thought the gearbox was smooth and felt positive with no unexpected neutrals. The clutch was light and progressive with no slip or drag. The handling was a little heavier than some of my other machines -- particularly the BSAs -- but it instilled immediate confidence. I've yet to scrape the footpegs but give me a few more miles…!
'It's a smooth engine with no vibration to speak of either through the footrests, seat or handlebars (but then I was taking it easy for running in). The engine appears to be oil tight so far: thank goodness, because that was the reason for the strip down!'
Neil finished the day by tightening down the cylinder head, then set off the next morning on the second leg of the shake down - a further 120 gentle miles. He discovered that, as with many AMC bikes of this period, the primary chaincase is prone to leaking (you can try to fix it until the cows come home, or chalk it up to be ing 'one of those things'!), and noticed that a couple of the tank mounting bolts and rubbers had worked loose with the vibration. Nothing unusual there - which is why it pays to clean down the bike after a decent ride and just check that nothing has worked itself free.
However, there was something strange going on with the rear wheel spindle. It caused a speedo hiccup and when Neil took the spindle out he 'found that the oil seal cup and washer were incorrectly assembled. Apparently this is a common mistake as in most rebuilds people logically fit the oil seal into the cup. This looks right but in fact is totally wrong! You learn something every day.
So what does Neil think of the Matchless 600, now that he's clocked up some more miles? 'The good news is that she always starts first or second kick... most important. And I've decided the handling is NOT 'heavy' as I first described. The bike feels sturdy and robust, and so the handling is predictable and reassuring. Choose what words one will, but it's unfair to say that it's heavy!
So the G11 passed its entrance exam, and is now a full time member of the Classic Bike Provence team. If you'd like to ride it - or any of the other classics, British or Japanese - in the CBP stable, you can contact their UK office on 0207 871 0471 or call 00 33 (0)442 287610 in France. There are plenty of tour dates remaining for this year - or you can try a classic taster, and get used to riding an old bike in sun-drenched splendour, without any traffic to distract you.
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However, these days the affordable and reliable 600s shouldn't be discounted - FW reckons they're 'very pleasant to ride, with a generous spread of power and a distinctive style. They sound good, too. The 600 engine is fairly unstressed, proving little quicker but more flexible than its smaller stablemate.' When new, a G11 would reach just under the ton, and the tweaked sports version was the first sports-roadster bike to travel 100 miles around MIRA's test track within one hour. So, even 50 years later, a G11 should prove to be an entertaining ride for travellers in Provence.The CBP G11 had indeed been rebuilt but it was suffering from a major crankcase oil leak. Much cross-Channel correspondence ensued, with Steve the Toaster shuttling parts down to Provence and helping to wield spanners, while FW provided advice and the chaps at AMC Classic Spares came up with the correct spare parts. It transpired that when the engine was last re-assembled someone had left out a critical gasket - that never helps if you're aiming for an oil-tight engine!
With the work complete, Neil could take the G11 for a shake-down ride - this was a moment of truth indeed because he'd not ridden a Matchless before, and he wanted to be sure that the bike was suitable for his holidaymaking customers.
'I had the first ride out -- some 25 miles cruising along at 40 to 55mph,' reported Neil immediately after the ride. 'This is the first time in two years the bike has been ridden and she ran beautifully. Lots of 'firsts' here as it was the first time I had ridden a Matchless… and my first impressions were very favourable. This is a machine which epitomises what classic motorcycling with CBP is all about. A relaxed riding speed, comfortable seating position, nice burble to the exhaust without being obtrusive, easy starter... and a great looking machine to boot!
'I thought the gearbox was smooth and felt positive with no unexpected neutrals. The clutch was light and progressive with no slip or drag. The handling was a little heavier than some of my other machines -- particularly the BSAs -- but it instilled immediate confidence. I've yet to scrape the footpegs but give me a few more miles…!
'It's a smooth engine with no vibration to speak of either through the footrests, seat or handlebars (but then I was taking it easy for running in). The engine appears to be oil tight so far: thank goodness, because that was the reason for the strip down!'
Neil finished the day by tightening down the cylinder head, then set off the next morning on the second leg of the shake down - a further 120 gentle miles. He discovered that, as with many AMC bikes of this period, the primary chaincase is prone to leaking (you can try to fix it until the cows come home, or chalk it up to be ing 'one of those things'!), and noticed that a couple of the tank mounting bolts and rubbers had worked loose with the vibration. Nothing unusual there - which is why it pays to clean down the bike after a decent ride and just check that nothing has worked itself free.
However, there was something strange going on with the rear wheel spindle. It caused a speedo hiccup and when Neil took the spindle out he 'found that the oil seal cup and washer were incorrectly assembled. Apparently this is a common mistake as in most rebuilds people logically fit the oil seal into the cup. This looks right but in fact is totally wrong! You learn something every day.
So what does Neil think of the Matchless 600, now that he's clocked up some more miles? 'The good news is that she always starts first or second kick... most important. And I've decided the handling is NOT 'heavy' as I first described. The bike feels sturdy and robust, and so the handling is predictable and reassuring. Choose what words one will, but it's unfair to say that it's heavy!
So the G11 passed its entrance exam, and is now a full time member of the Classic Bike Provence team. If you'd like to ride it - or any of the other classics, British or Japanese - in the CBP stable, you can contact their UK office on 0207 871 0471 or call 00 33 (0)442 287610 in France. There are plenty of tour dates remaining for this year - or you can try a classic taster, and get used to riding an old bike in sun-drenched splendour, without any traffic to distract you.
Matchless Silver Hawk
The Silver Hawk was created in tough economic times during the era of the Great Depression. A new generation of the Collier family had not long taken the helm of the Matchless concern and, although finances were tight, Harry, Bert and Charlie Collier were keen to incorporate cutting edge innovation in the designs of their new luxury models. The British motorcycling scene had been dominated by single-cylinder bikes for many years, but 'multis' were becoming all the rage. Two cylinders might not seem very exciting now, but back then any motorcycle with more than one lung was considered to be a bit daring. The Colliers kept pace with Edward Turner who introduced the Square Four over at Ariel. Ariel's first four was a 500; Matchless countered with a 400cc narrow-angle V-twin, the Silver Arrow, and then the 600cc four-cylinder Hawk.
The V-twin Silver Arrow wasn't a great success although it pioneered several of the features which Bert Collier adopted for the Hawk. The Arrow was sophisticated but not particularly fast; comfortable and quiet, but not quick. It was adored by the press (it gave them plenty to write about!) but sold slowly, so something with a greater turn of speed was called for. The V4 Silver Hawk delivered the goods with a four-cylinder, 592cc, 26bhp engine capable of propelling the motorcycle to 85mph. Importantly, the Hawk also had a chassis and suspension to match its engine's potential.
In their own words, the Colliers described the Silver Hawk as; 'the most fascinating machine to ride that has ever been built. It combines the silence, smoothness and comfort of the most expensive motor car with a Super-Sports performance. On top gear alone, the machine will run from as low as 6mph to over 80mph, while the acceleration given by the four-cylinder overhead camshaft engine in conjunction with the four-speed gearbox must be experienced to be believed. This is the only four-cylinder machine in the world equipped with a Spring Frame.'
The new Matchless motor was essentially two narrow-angle V-twins mounted side by side on a one-piece cast block, with a single-piece cylinder head housing a bevel-driven overhead camshaft. Both V-twins had crankshafts which were set across the frame and thus avoided a 90-degree turn in the transmission (although an alternative layout might have turned the engines through a right angle and used a shaft drive to the rear wheel. That suggestion might be 80 years too late to be of any help…)
The four valves in the top end were completely enclosed and well lubricated, and could be easily accessed by hand to be adjusted. Fuel was delivered to the combustion chamber by a single, centrally mounted Amal carb. The compact engine used roller bearing big ends and a chunky, built-up, two-throw crankshaft that featured substantial cheeks which doubled as flywheels. Positively lubricated phosphor bronze bushes were at either end of the crankshaft with a central roller bearing. The oil tank lived at the front of the engine, by the frame downtube, and bolted directly to the crankcase, thus removing the need for unsightly external oil lines. It is indeed a very tidy design, as you can see from the photos.
Four gear ratios were normally selected by hand; the primary drive chain lived in an oil bath and final drive was also by chain. Drive for the Lucas dynamo/coil ignition system was provided by skew gears from the vertical camshaft tower on the right of the engine, which itself is decorated with the most glorious model badge to ever grace a motorcycle. (I'm not biased. No. Not in the slightest).
With dimensions of 51mm by 73mm, the Hawk retained the relaxed, long-stroke feel of many vintage engines, helped by its mild compression ratio of 6.1:1. Although the Hawk's engine suffered somewhat from overheating (less than did the Square Four of the period), it was extremely easy to start and could be turned over by hand. Once on the move it would pull smoothly from below 10mph in top gear, although the model's much-vaunted smooth sophistication lessened as it neared its top velocity. Matchless claimed that the Hawk engine was 'vibrationless and silent in operation and capable of very high output', Cyril Ayton reckoned that 'the Hawk seemed to become more frenzied with increasing speed'. By contrast Ariel's Square Four gained a reputation for more effortless acceleration - but we should remember that it wasn't until a whole half century later that Honda finally cracked the basics of a competent V4 motorcycle engine.
However, the V4 engine wasn't the only remarkable thing about the Silver Hawk. It used a similar chassis to the Arrow, with an extremely advanced form of rear suspension. The cantilever triangulated system featured two springs set horizontally underneath the separately spring saddle, with two mechanical friction dampers on either side of the springs. This really did live up to its potential and worked well with the girder forks (which could be adjusted by the rider while on the move) at the front, providing a supremely comfortable ride for the time.
The Colliers also included an adjustable linked braking system on the Hawk. 'The brakes are well engineered' said Titch Allen, who found that the eight-inch drums worked extremely well with the rear suspension, although he wasn't a great fan of the linked system. 'I cannot get used to the forks chattering under braking when I have only used the footbrake.
Another innovation was the sprung centrestand - rarely seen at the time, when front or rear wheel stands were the norm. Matchless also offered the option of a positive stop, foot controlled gearchange, for purchasers willing to spend an additional 30 bob. The 370lb Silver Hawk was the top of the range machine and in De Luxe trim came with full electric lighting and horn, a proper ignition switch and indicator light, speedo and oil indicator. If you wanted the detachable luggage carrier it would cost you an extra fifteen shillings, however!
Apart from some issues with overheating when run at high speeds for sustained periods, the first version of the Hawk also had a habit of guzzling oil (a modification for 1932 helped with that problem). Setting up the bevel gears correctly was tricky for home mechanics, so it was common for them to whine or rattle in a manner which would feel very familiar to owners of much later bevel-drive Ducati twins.
The Silver Hawk cost £72 new in 1933; £5 more than Ariel's Square, and the price of the Matchless rose to nearly £79 in the four years of its production run. Just 550 Silver Hawks were sold between 1931 and 1935. These days the Silver Hawk sells for between £30,000 and £45,000 depending on its condition. A complete and unrestored example, in 'barn find' condition, sold for £28,000 in 2009. A recently restored Hawk fetched £35,000 at auction in October 2010; that bike looked very handsome indeed but was effectively a museum piece.
In 1931 Torrens of The Motor Cycle reported that 'at 50mph the engine of the machine was unnoticeable and barely a sound from engine or exhaust could be heard. The spring frame was excellent and the only guide to its presence was the exceptional comfort of the machine.' The handling was 'just about perfect; there was no tail wag, chopping or pitching, even when roughish bends were taken nearly flat out.' He believed that 'no finer machine had ever left the Matchless works, and that on all-round performance it had very, very few rivals.'
Mick Walker reckons that the Silver Hawk was 'in many ways a brilliant design which was unfortunate enough to be conceived at just the wrong moment in history… The majority of customers for whom the Silver Hawk had been designed were simply unable to make a purchase of such a luxury item in those times of economic gloom… It was a notable design worthy of a better fate.
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The V-twin Silver Arrow wasn't a great success although it pioneered several of the features which Bert Collier adopted for the Hawk. The Arrow was sophisticated but not particularly fast; comfortable and quiet, but not quick. It was adored by the press (it gave them plenty to write about!) but sold slowly, so something with a greater turn of speed was called for. The V4 Silver Hawk delivered the goods with a four-cylinder, 592cc, 26bhp engine capable of propelling the motorcycle to 85mph. Importantly, the Hawk also had a chassis and suspension to match its engine's potential.In their own words, the Colliers described the Silver Hawk as; 'the most fascinating machine to ride that has ever been built. It combines the silence, smoothness and comfort of the most expensive motor car with a Super-Sports performance. On top gear alone, the machine will run from as low as 6mph to over 80mph, while the acceleration given by the four-cylinder overhead camshaft engine in conjunction with the four-speed gearbox must be experienced to be believed. This is the only four-cylinder machine in the world equipped with a Spring Frame.'
The new Matchless motor was essentially two narrow-angle V-twins mounted side by side on a one-piece cast block, with a single-piece cylinder head housing a bevel-driven overhead camshaft. Both V-twins had crankshafts which were set across the frame and thus avoided a 90-degree turn in the transmission (although an alternative layout might have turned the engines through a right angle and used a shaft drive to the rear wheel. That suggestion might be 80 years too late to be of any help…)
The four valves in the top end were completely enclosed and well lubricated, and could be easily accessed by hand to be adjusted. Fuel was delivered to the combustion chamber by a single, centrally mounted Amal carb. The compact engine used roller bearing big ends and a chunky, built-up, two-throw crankshaft that featured substantial cheeks which doubled as flywheels. Positively lubricated phosphor bronze bushes were at either end of the crankshaft with a central roller bearing. The oil tank lived at the front of the engine, by the frame downtube, and bolted directly to the crankcase, thus removing the need for unsightly external oil lines. It is indeed a very tidy design, as you can see from the photos.
Four gear ratios were normally selected by hand; the primary drive chain lived in an oil bath and final drive was also by chain. Drive for the Lucas dynamo/coil ignition system was provided by skew gears from the vertical camshaft tower on the right of the engine, which itself is decorated with the most glorious model badge to ever grace a motorcycle. (I'm not biased. No. Not in the slightest).
With dimensions of 51mm by 73mm, the Hawk retained the relaxed, long-stroke feel of many vintage engines, helped by its mild compression ratio of 6.1:1. Although the Hawk's engine suffered somewhat from overheating (less than did the Square Four of the period), it was extremely easy to start and could be turned over by hand. Once on the move it would pull smoothly from below 10mph in top gear, although the model's much-vaunted smooth sophistication lessened as it neared its top velocity. Matchless claimed that the Hawk engine was 'vibrationless and silent in operation and capable of very high output', Cyril Ayton reckoned that 'the Hawk seemed to become more frenzied with increasing speed'. By contrast Ariel's Square Four gained a reputation for more effortless acceleration - but we should remember that it wasn't until a whole half century later that Honda finally cracked the basics of a competent V4 motorcycle engine.
However, the V4 engine wasn't the only remarkable thing about the Silver Hawk. It used a similar chassis to the Arrow, with an extremely advanced form of rear suspension. The cantilever triangulated system featured two springs set horizontally underneath the separately spring saddle, with two mechanical friction dampers on either side of the springs. This really did live up to its potential and worked well with the girder forks (which could be adjusted by the rider while on the move) at the front, providing a supremely comfortable ride for the time.
The Colliers also included an adjustable linked braking system on the Hawk. 'The brakes are well engineered' said Titch Allen, who found that the eight-inch drums worked extremely well with the rear suspension, although he wasn't a great fan of the linked system. 'I cannot get used to the forks chattering under braking when I have only used the footbrake.
Another innovation was the sprung centrestand - rarely seen at the time, when front or rear wheel stands were the norm. Matchless also offered the option of a positive stop, foot controlled gearchange, for purchasers willing to spend an additional 30 bob. The 370lb Silver Hawk was the top of the range machine and in De Luxe trim came with full electric lighting and horn, a proper ignition switch and indicator light, speedo and oil indicator. If you wanted the detachable luggage carrier it would cost you an extra fifteen shillings, however!
Apart from some issues with overheating when run at high speeds for sustained periods, the first version of the Hawk also had a habit of guzzling oil (a modification for 1932 helped with that problem). Setting up the bevel gears correctly was tricky for home mechanics, so it was common for them to whine or rattle in a manner which would feel very familiar to owners of much later bevel-drive Ducati twins.
The Silver Hawk cost £72 new in 1933; £5 more than Ariel's Square, and the price of the Matchless rose to nearly £79 in the four years of its production run. Just 550 Silver Hawks were sold between 1931 and 1935. These days the Silver Hawk sells for between £30,000 and £45,000 depending on its condition. A complete and unrestored example, in 'barn find' condition, sold for £28,000 in 2009. A recently restored Hawk fetched £35,000 at auction in October 2010; that bike looked very handsome indeed but was effectively a museum piece.In 1931 Torrens of The Motor Cycle reported that 'at 50mph the engine of the machine was unnoticeable and barely a sound from engine or exhaust could be heard. The spring frame was excellent and the only guide to its presence was the exceptional comfort of the machine.' The handling was 'just about perfect; there was no tail wag, chopping or pitching, even when roughish bends were taken nearly flat out.' He believed that 'no finer machine had ever left the Matchless works, and that on all-round performance it had very, very few rivals.'
Mick Walker reckons that the Silver Hawk was 'in many ways a brilliant design which was unfortunate enough to be conceived at just the wrong moment in history… The majority of customers for whom the Silver Hawk had been designed were simply unable to make a purchase of such a luxury item in those times of economic gloom… It was a notable design worthy of a better fate.
1941 Matchless G3L WD
The G3L was an extremely popular DR's mount during WW2 because, unlike most other machines, it was fitted with Teledraulic front suspension. This made for a much more comfortable ride than did the standard girder forks fitted to most other military machines. By the end of the war, Matchless had built over 80,000 G3 and G3L motorcycles for the armed forces. The 'L' stands for 'Light', reflecting the fact that the prewar G3 was a substantial machine and it needed to lose some 60lb to be put into service during the conflict. After the war, the first civilian G3Ls were much the same as the military machines - but they were painted black instead of green.
If you are considering buying a similar G3L today, then you can expect to pay between £1700 and £3000. It's cheaper to buy one in civilian trim because the military motorcycles have developed something of a cult following, and finding exactly the correct WD equipment can get very tricky. However, you can find later G3s in military trim because the MOD continued to use the bikes into the 1960s.
Basil's Matchless was restored to standard spec for a WW2 machine and was given 'a first class total rebuild' without any obvious modifications 'so it's accurate for the period', and Basil reckons it is 'perfect… just as you would expect a military machine to be.'
He recommends Russell Motors for their 'good service' and Hawker Electrical for their electronic dynamo regulator.
Since the rebuild Basil has clocked up around 3000 miles, taking the 350cc single to shows and galas and on club runs. It always attracts attention. 'When we do shows it's amazing how many chaps of that era come and tell you tales from the days when we all served our country' says Basil. 'Then they ask if they can sit on it and have their photo taken!'
So Basil is really happy with how the G3L turned out, even though he didn't set out to own one.
'It's a belter and has won lots of trophies. You just couldn't make it any better than it is. It's ready for anything!'
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If you are considering buying a similar G3L today, then you can expect to pay between £1700 and £3000. It's cheaper to buy one in civilian trim because the military motorcycles have developed something of a cult following, and finding exactly the correct WD equipment can get very tricky. However, you can find later G3s in military trim because the MOD continued to use the bikes into the 1960s.Basil's Matchless was restored to standard spec for a WW2 machine and was given 'a first class total rebuild' without any obvious modifications 'so it's accurate for the period', and Basil reckons it is 'perfect… just as you would expect a military machine to be.'
He recommends Russell Motors for their 'good service' and Hawker Electrical for their electronic dynamo regulator.
Since the rebuild Basil has clocked up around 3000 miles, taking the 350cc single to shows and galas and on club runs. It always attracts attention. 'When we do shows it's amazing how many chaps of that era come and tell you tales from the days when we all served our country' says Basil. 'Then they ask if they can sit on it and have their photo taken!'
So Basil is really happy with how the G3L turned out, even though he didn't set out to own one.
'It's a belter and has won lots of trophies. You just couldn't make it any better than it is. It's ready for anything!'
Matchless G12
The Matchless G12 is a British motorcycle made by Associated Motorcycles at the former Matchless works in Plumstead, London. Developed in 1958 specifically to capture the potentially lucrative US market, the last G12 was produced in 1966.
Development
Matchless G12 The Matchless G12 was one of the last motorcycles under the Matchless name and was also produced as the AJS Model 31 by the same company. Designer by Phil Walker, AMC knew that it had to be a 650 cc (39.7 cu in) but wanted to use as many parts from the Model 11 as possible. The cylinders could not be bored out further so the stroke was lengthened from 72.8 to 79.3 mm (2.87 to 3.12 in), resulting in a capacity of 646 cc (39.4 cu in). This meant developing a new crankshaft and primary chaincase, which also provided the opportunity to add a Lucas alternator. Volume production began in September 1958.
Matchless G12 De Luxe In 1959 the G12 was redesigned and modernised as the De Luxe with a new full cradle tubular duplex frame and a new cylinder head. Vibration had always been a problem, so the crankshaft was upgraded to nodular iron. Capable of 100 mph (160 km/h) performance, the G12 became popular with the American market.
Matchless G12 CS The Matchless G12 CS (sometimes referred to as the CS X) was an off-road version of the Matchless G12 with improved ground clearance and a slightly upswept exhaust and an 8.5:1 compression ratio. It was not a trials competition machine but instead aimed at the 'desert racer' market in the US.
Matchless G12 CSR The Matchless G12 CSR designation officially stood for "Competition/Sprung/Roadster," the same nomenclature used with the G80 and G50 models. It is mistakenly referenced as Competition/Sport/Road. It was dubbed the Coffee Shop Racer by its rivals. With its distinctive two-into-one 'siamese' exhaust system and upgraded camshafts the CSR was a high performance motorcycle with what was, at the time, a high compression ratio of 8.5:1, distinguishing it and the G12 CS from the other G12 models, having a 7.5:1 compression ratio. The factory diverted Chief Engineer Jack Williams from AJS 7R development to address the problems with leaks and vibration and modify the bikes for racing - with the result that Ron Langston and Don Chapman won the prestigious Thruxton 500 long distance endurance race on the AJS Model 31 counterpart to the G12. Encouraged by this victory in 1963 the G12 CSR gained the name Monarch and twin carburettors (the AJS version was renamed the Hurricane).
Matchless G15/45 In 1964 the CSR gained Norton brakes and forks, and the following year a Norton Atlas 750 cc (45.8 cu in) engine replaced the trouble prone AMC unit. In 1962 and 1963, AMC had produced a limited run of 212 touring motorcycles of 738 cc (45.0 cu in) displacement using an enlarged version of the G12 AMC-designed engine, but these bikes—which were given the model designation "G15/45"—proved even less reliable than the 650 cc (39.7 cu in) version when ridden hard. So AMC's original plans to develop a 750 cc desert racer version were abandoned. If successful, this could have saved the company as there was a huge un-met demand in the US for powerful desert racers to compete in endurance events. By this time the company were in financial trouble and production ended in 1966.
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Development
Matchless G12 The Matchless G12 was one of the last motorcycles under the Matchless name and was also produced as the AJS Model 31 by the same company. Designer by Phil Walker, AMC knew that it had to be a 650 cc (39.7 cu in) but wanted to use as many parts from the Model 11 as possible. The cylinders could not be bored out further so the stroke was lengthened from 72.8 to 79.3 mm (2.87 to 3.12 in), resulting in a capacity of 646 cc (39.4 cu in). This meant developing a new crankshaft and primary chaincase, which also provided the opportunity to add a Lucas alternator. Volume production began in September 1958.
Matchless G12 De Luxe In 1959 the G12 was redesigned and modernised as the De Luxe with a new full cradle tubular duplex frame and a new cylinder head. Vibration had always been a problem, so the crankshaft was upgraded to nodular iron. Capable of 100 mph (160 km/h) performance, the G12 became popular with the American market.
Matchless G12 CS The Matchless G12 CS (sometimes referred to as the CS X) was an off-road version of the Matchless G12 with improved ground clearance and a slightly upswept exhaust and an 8.5:1 compression ratio. It was not a trials competition machine but instead aimed at the 'desert racer' market in the US.
Matchless G12 CSR The Matchless G12 CSR designation officially stood for "Competition/Sprung/Roadster," the same nomenclature used with the G80 and G50 models. It is mistakenly referenced as Competition/Sport/Road. It was dubbed the Coffee Shop Racer by its rivals. With its distinctive two-into-one 'siamese' exhaust system and upgraded camshafts the CSR was a high performance motorcycle with what was, at the time, a high compression ratio of 8.5:1, distinguishing it and the G12 CS from the other G12 models, having a 7.5:1 compression ratio. The factory diverted Chief Engineer Jack Williams from AJS 7R development to address the problems with leaks and vibration and modify the bikes for racing - with the result that Ron Langston and Don Chapman won the prestigious Thruxton 500 long distance endurance race on the AJS Model 31 counterpart to the G12. Encouraged by this victory in 1963 the G12 CSR gained the name Monarch and twin carburettors (the AJS version was renamed the Hurricane).
Matchless G15/45 In 1964 the CSR gained Norton brakes and forks, and the following year a Norton Atlas 750 cc (45.8 cu in) engine replaced the trouble prone AMC unit. In 1962 and 1963, AMC had produced a limited run of 212 touring motorcycles of 738 cc (45.0 cu in) displacement using an enlarged version of the G12 AMC-designed engine, but these bikes—which were given the model designation "G15/45"—proved even less reliable than the 650 cc (39.7 cu in) version when ridden hard. So AMC's original plans to develop a 750 cc desert racer version were abandoned. If successful, this could have saved the company as there was a huge un-met demand in the US for powerful desert racers to compete in endurance events. By this time the company were in financial trouble and production ended in 1966.
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