Tag Archives: Retrospective

Retrospective: 1958-1966 Matchless G12/CS/CSR 650

1961 Matchless G12CS
1961 Matchless G12CS. Owner: Steve Eorio, Paso Robles, California.

The 1950s and ’60s were the era of the UBM — Universal British Motorcycle — a parallel OHV twin sitting upright in the frame, in the 500cc to 750cc range. The original UBM was the Triumph 5T Speed Twin of 1938, soon to be copied by half a dozen of the major British motorcycle companies. Matchless, which built its first motorcycle at the Plumstead works in southeast London around 1901, came up with its own version in 1948, the 498cc G9, with a 66 x 72.8mm bore and stroke. And a fully sprung frame, with a swingarm rear suspension.

It should be noted that in the 1930s Matchless bought the AJS marque and the company became Associated Motor Cycles, Ltd., or AMC, the major difference between the two brands being the lettering on the gas tank.

The G9 engine differed from other UBMs in that it had a third bearing on the crankshaft, between the two connecting rods, to give added strength. The engine’s dry sump lubrication system used the camshaft to run two oil pumps, one on each side of the crank, aiding in efficient lubrication; apparently these engines could go 75,000 miles before any major work was needed. Quite remarkable for a UBM of the era, when top-end jobs were often done at 20,000 miles, bottom-end at 40,000.

1961 Matchless G12CS

The two cylinders were separate, as were the heads, and while this seemed to work well with the 500, as the engine grew larger the lack of rigidity appeared to enhance vibration. During the 1950s most factories increased the size of the engine, with 650cc being considered the maximum reasonable size for a UBM, due to those vibratory concerns. In 1955 Matchless elected to bore out the engine to 72mm for an increase to 593cc — called a 600, designated as a G11. This was followed by the G11CS, or Competition Sprung, a street-legal scrambler with easily removable lights, and the G11CSR, a more roadworthy version, often called the Coffee Shop Racer. The CS models came with higher compression ratios and other performance enhancements…and often more problems. The frame used a single downtube to meet up with the full cradle holding the engine.

In 1958 Matchless offered 17 different models, including the first G12 650. The very important American market had been demanding that 650, the dealers needing it to compete with the Triumph and BSA 650s. Small problem: the engine could not be bored out any more. Solution: increase the stroke to 79.3mm, or 646cc. That was the G12, with the basic road-going model having valanced fenders and a reliable 7.5:1 compression ratio, and two sportier CS models with an 8.5:1 compression ratio and light alloy fenders.

1961 Matchless G12CS

The restroked engine required a new crankshaft, made of “nodular” iron, which flexed enough to reduce vibrations. It was also designed to incorporate a Lucas alternator, though still with six-volt electrics. A new frame with twin downtubes now welded to the full cradle was developed, which did help in reducing the vibration inherent in a 650 vertical twin using a 360-degree crankshaft, although the single-tube frame was also used. The motorcycle seen here, which was built from bits and pieces, has a 1961 G12 engine in a 1959 single downtube frame. An AMC Teledraulic fork is up front, a pair of Girling shock absorbers at the back.

Gas tanks varied in size according to the model and year, but this ’61 G12CS carried only two gallons, all you would need in a race, and was said to weigh 425 pounds with a full tank. And with 5.3 pints of oil in the reservoir.

Other changes occurred over the G12’s years, including 12-volt electrics, sending out decent visibility from the seven-inch headlight. The basic G12 had 18-inch wheels, while this CS was running 19-inchers. Distance between the axles was a little more than 55 inches. Brakes were single-leading-shoe drums, an eight-incher on the front, seven on the back.

1961 Matchless G12CS

One interesting bit of history is that the Matchless marque was originally sold in the U.S. by Californian Frank Cooper, who became the AMC importer around 1946. He did quite well selling singles to win desert races, though the twins were not as popular.

In 1953, AMC acquired financially troubled Norton, although Norton production and sales remained quite separate, the U.S. importer being Joe Berliner, or J.B. Then, in 1960, AMC bought the Indian Sales Corp., which had been selling rebadged Royal Enfields — this was to get the Indian dealers, such as they were, to sell Matchboxes rather than Royal Oilfields. And AMC summarily fired Cooper, after 14 years of good work.

However, AMC filed for bankruptcy in 1962 (Cooper must have laughed), resulting in Matchless being merged more closely with Norton, and Berliner having to deal with Matchless as well. In early 1963, J.B. Matchless Corp. put a full-page ad in Cycle magazine promoting the G12CS and G12CSR…along with the 750cc G15 Matchless, which looked surprisingly like the Norton Atlas model that had appeared in 1962. In 1963 that old 1952 Matchless/Norton arrangement, keeping them separate, changed drastically as bill collectors were pounding on both doors, and Norton production moved from its old Birmingham factory 100 miles southeast to Plumstead.

Not surprisingly, interest in the G12 waned considerably. The last Matchless ad I could find in a U.S. moto-mag was in Cycle’s July 1966 issue, featuring the Atlas-based G15, and mentioning one G12CSR and two G80 singles. At the time British bureaucrats, knowing nothing about motorcycles, thought they could save the industry by merging Matchless, AJS and Norton into the company of an affluent entrepreneur and racecar driver, Dennis Poore. Poore was already looking after the Villiers engineering firm, which made most of the British two-stroke motorcycle engines. The Matchless and AJS names dropped from sight, and the new company was called Norton-Villiers.

Source: RiderMagazine.com

Retrospective: 1967-1969 Kawasaki C2TR 120 Road Runner

1967 Kawasaki C2TR 120 Road Runner. Owner: Cliff Schoening, Bremerton, Washington.

This was a little cutie, and inexpensive, too. Just $430 ($3,200 today) would get you this minimalist high-piped single in 1967. Not that the bike was set up for quarter-mile times, but a real lightweight rider with a strong wind at his back might break 20 seconds. What do you expect from a 120?

Kawasaki was the last of the Japanese Big Four to get into the American market, when an American-owned subsidiary appeared in Chicago in 1963 offering a few two-stroke singles. Early ads promoted its connection with the Kawasaki Aircraft Co. Ltd., which was shut down following WWII but started building planes again in 1954. The big K soon saw the error of its ways and set up a Kawasaki-owned operation in Los Angeles in 1965, sensibly giving the Americans involved a good deal of say in what should be built for the U.S. market. 

Two-stroke singles were the rage, cheap and simple, the essential engine having just three moving parts. In the home market Kawasaki knew that winning on Sunday meant selling on Monday, so it worked hard to score points in the racing world of Japan, using rotary valves instead of the old-fashioned piston-port design and applying the same sophistication to its street bikes.

In 1964 Kawasaki showed the C2SS (Street Scrambler) to the home market, an attractive little single intended for the pavement, with a stylish upswept exhaust pipe. It also offered the “trail kit,” an optional bundle of pieces that would turn this into a proper trail bike…of sorts. The kit had an adapter for raising the front fender, a luggage rack and a second rear sprocket mounted next to the stock one. The stock sprocket had 37 teeth and a first-gear ratio of 25:1. In a few minutes time the rider could loosen a few bolts and slide the new 59-tooth sprocket over the old one, giving a ratio of 40:1. Good for going up Mount Fuji!

In 1967 two very similar C2 120 models came to the U.S., the TR (Trail Rider) and the SS, both with street-scrambler styling. Obviously the word was that Americans thought that an upswept exhaust system was cool, and that occasionally leaving the pavement was great fun. The bikes were also given the Road Runner name. Most of us can remember the Road Runner cartoon character, a bird that was always being chased across the desert by Wile E. Coyote. The owner’s manual had an illustration of the bird. Obviously the California fellows thought this would be a great name for the bike, but there is no mention of whether the KMC execs ever asked “Looney Tunes” for permission.

The TR was slightly more off-road oriented, having knobbier tires, a smaller front fender mounted well above the wheel, slightly shortened saddle, bash plate and a big luggage rack — for carrying all that camping gear for the trip into the wilderness. Although the engine was a bit on the small side for anyone wanting to tackle rough, steep terrain.

The cylinder was aluminum with a cast iron liner and was almost square, with a 53mm bore, 52.5mm stroke for an actual 115cc and a compression ratio of 6.7:1. The factory was claiming 11.5 horses at 7,000 rpm, which was a small herd from a small paddock, with one pony for every 10cc; very neat. The advertised torque curve — what there was of it — was pleasantly flat, with 6.5 lb-ft at 2,000 rpm, maxing out at 9.1 lb-ft at 5,000 and dropping off to 7 lb-ft at an over-revved 8,000.

An 18mm Mikuni carburetor was coupled with an automatic lubrication system, called Superlube. The oil tank, easily accessible under the seat, delivered the lubricant (the amount being dependent on the throttle opening) to the front of the rotary valve, where it would mix with the gas. Fouling plugs was a thing pretty much of the past.
Oil-level viewing was on the left side panel.

The engine cases, made of aluminum alloy, held the cylinder up front, gearbox behind. Power ran back to a four-speed transmission of the rotary style, which meant the rider could go all the way around from fourth directly to neutral to first gear, or shift backwards through third and second. The shift lever was heel and toe so downshifting could be done without besmirching the rider’s white bucks. Remember those? 

The chassis did have some off-road pretensions, the photo model having a curious optional brace bolted to the lower legs of the fork and looping over the wheel in front of the fender. It may also have fended off the brush that an enthusiastic rider might get into. The full double-cradle frame was made of mild steel and very strong by the swingarm pivot. The double-cradle aspect extended to a pair of tubes forming the backbone under the tank and then going farther back from the main cradle to support the saddle and the tops of the two shock absorbers. Even with the aforementioned bash plate, there was more than six inches of ground clearance. Suspension was, well, not competitive, but quite adequate for the college-aged fellow who liked having a coed pressed against his back as they cruised the city streets.

Wheels were 18 inches at both ends, with small drum brakes that worked OK considering the speeds the Road Runner went. Forty-five inches between the axles made for a short machine. With 1.7 gallons of gas in the tank, weight was a modest 186 pounds.

The C2 Road Runners went away late in 1969; did “Looney Tunes” have anything to do with that?

Source: RiderMagazine.com

Retrospective: 1971-1977 Healey 1000/4

1971 Healey 1000/4, Prototype #2
1971 Healey 1000/4, Prototype #2. Owner: Thomas Harper, Garden Grove, California.

This has to be one of the least-known motorcycles built since the end of World War II, with an Ariel 4G Mark II Square Four engine bolted into a Roger Slater frame. The photo model is one of the two prototypes, and lacks some of the amenities of the production versions – such as the side panels.

The Healey 1000/4 does not appear to be listed in any of the popular motorcycle encyclopedias, and the only major mention to be found in motorcycle histories are some three pages in Roy Bacon’s “Ariel – The Postwar Models.” I remember reading something about it in an American motorcycle magazine in the early 1970s, but that is about it. After punching a few keys on my computer a dozen different sites come up, with varied information. Any number of articles have probably been written about this bike in British magazines, but apparently those stories are not online.

Starting at the beginning means back to the first 997cc OHV Ariel 4G engine. An earlier, smaller, OHC version existed, but we’ll leave that out. That 4G was around from 1936 to 1959, with Ariel advertising Squariels that last year, along with the new two-strokes.

1971 Healey 1000/4, Prototype #2
1971 Healey 1000/4, Prototype #2

The biggest problem with an air-cooled square four is that the front cylinders do fine, but the rear pair can overheat. Over the quarter-century of the 4G’s production – minus a couple of years due to the war – there were continuous upgrades in the run that totaled some 12,000 bikes. The final Mark II version had an alloy cylinder block with pressed-in barrels, and a lightweight alloy cylinder head with a slightly X-shaped induction manifold feeding all four cylinders via just one SU carburetor. A single transverse camshaft operated the eight valves. Two separate cast aluminum exhaust manifolds ran four separate header pipes, better for cooling. The dry sump engine had eight pints of oil in the reservoir. The oil-bathed primary chain ran back to a dry clutch, and the four-speed gearbox was a Burman GB.

The original purpose of this model was to haul sidecars, so it did not have much in the way of horsepower – around 40 with the 7.2:1 compression – but bags of torque. Sprinting, the British word for drag racing, was popular in the 1950s, and a stock Mark II, being rather hefty, ran in the mid-15s with a speed of around 85 mph. One fellow put a supercharger on a Vincent V-twin and turned 11.3 seconds in 1958, but when somebody tried that with a 4G, it ended with a big BANG! as the cylinders separated from the crankcase.

1971 Healey 1000/4, Prototype #2
1971 Healey 1000/4, Prototype #2

A pair of brothers, George and Tim Healey, liked playing around with the 4Gs, and were sprinting them in the 1960s. Some time after Ariel shut down 4G production, the Healeys began gathering up the unsold stock. They had a shop in Redditch, a few miles south of the Ariel factory, and by 1967 the spares were running out and building replacement parts had become their full-time business, called the Ariel Sq4 Specialists. Then they decided to build their own motorcycle.

The old Square Four had a rather basic, and heavy, cradle frame, with an Ariel fork and Anstey-link plunger suspension at the back. The boys got in touch with Slater, who was making tubular spine-type frames for Vincents under an agreement with Fritz Egli (read about the Egli-Vincent here). Could he make a similar design for the Square Four? Not a problem. Essentially the engine was suspended from the frame, using half a dozen through-bolts. Up front a turnbuckle went from the steering head to the crankcase – just in case there might be a similar BANG!, this would prevent the crankcase from falling to the road. Slater built the prototypes, and production versions were manufactured in Redditch. The oil supply was held in the backbone, with the Healeys putting in an improved lubrication system and bolting an oil cooler on up front.

1971 Healey 1000/4, Prototype #2
1971 Healey 1000/4, Prototype #2

Metal Profile, a noted company that supplied forks to many British motorcycle companies, made the front fork, with tapered roller bearings used at the head. Rear shocks were by Girling, with two-way damping. Brakes were Italian, a powerful alloy drum having a pair of two leading shoes to slow the front wheel, single leading shoe at the back. Spoked wheels were both 18-inchers, with a 3.25 tire on the front, a 4.00 on the rear. The large gas tank on this prototype was a Slater design, but when the bike went into production, a more refined style was used. Instruments were speedo, tach, ammeter, sitting above a seven-inch headlight; a little clock was added to the production dash.

End result was somewhat impressive. Better cooling and lubrication allowed the compression ratio to be upped to 7.5:1. The Healey advertising said the 1000/4 put out 50 horsepower, 10 more than the old Mark II. Potential self-destruction kept radical changes at bay. Wheelbase was 57 inches, seat height 30 inches, and ground clearance at the unprotected sump was 7.5 inches. Most impressive was the weight, 355 pounds dry, 80 pounds less than the Mark II.

1971 Healey 1000/4, Prototype #2
1971 Healey 1000/4, Prototype #2

The first showing of a production bike was at Britain’s big motorcycle show in late 1971, and improvements went on over the next six years, ending with disc brakes and mag wheels, Italian fork and shocks. But the price was high, more than the new-in-1975 Gold Wing, and the company shut down in 1977. Precisely how many production models were built and sold is not known, but 18 seems to be a fair number. Plus nine or 10 kits for people who already had the 4G engine. Collectability? A Healey sold at auction for $40,000 in 2016.

Source: RiderMagazine.com

Retrospective: 1983 Suzuki XN85 Turbo

1983 Suzuki XN85D Turbo
1983 Suzuki XN85D Turbo. Owner: Cliff Schoening, Bremerton, Washington.

It would be entertaining to find out how much this little turbo cost Suzuki, as in development and manufacturing expenses versus sales. Probably it was a heckuva lot. In the very early 1980s turbo-mania was in the air, and Honda and Yamaha were the first out, with the four Japanese manufacturers prone to following one another.

Remember the Universal Japanese Motorcycle? Four cylinders in line, preferably with an overhead camshaft or two. Well, this was the turbo version, and while Honda used the OHV V-twin CX500 for its turbo, the rest were UJMs. In 1981 Suzuki came out with two 650cc UJMs, the chain-driven sporty E and the shaft-drive commuter G. Similar, but different. And Suzuki realized that this two-valve (per cylinder) motor was rapidly becoming obsolete, replaced by the four-valver. So how could it get a little more use from the powerplant? Put it in the Turbo!

1983 Suzuki XN85D Turbo

For the Turbo the engineers took the G’s one-piece forged crankshaft running on plain bearings, instead of the E’s roller bearings. Apparently plain bearings are smoother running. But the three 650s all had those two-valve heads, and twin overhead camshafts, that are the pretty much the same. However, everything on the Turbo’s engine, from connecting rods to cylinder studs, was strengthened.

Amusingly, when looking at the magazine spec sheets for all three bikes one notes that they all have a bore and stroke of 65 x 55.8, but the E and G are said to have 674cc capacity, while the Turbo is 673cc. The wonders of finite numbers. And copy editing.

After Honda and Yamaha began working on their turbos, probably a little corporate spying was going on. I can see the Suzuki marketing types charging into the CEO’s office and demanding that a turbo be built. Maybe somebody ran it past the financial department, maybe not. The XN85 appeared less than a year after the others, but more work had gone into the project, as it was truly a semi-new machine, excepting the reworked motor.

1983 Suzuki XN85D Turbo

As anybody who wrote a Ph.D. thesis on Japanese turbocharged motorcycles knows, that funny XN85 alpha-numeration came from Suzuki’s claim that the turbo 673cc put out 85 horsepower – which it might have, at the crankshaft. Fair enough, but the real world was more interested in what happened at the rear wheel, where a dyno measured 71 horses at 8,000 rpm. And close to 50 lb-ft of torque at 6,500 rpm. Which was quite respectable, and a lightweight rider might sneak into the 11s in the popular quarter-mile drags. The flow of air and a big oil cooler, with more than three quarts of oil in the system, kept the engine heat under control. A new aspect of the cooling system was the forcible spray of oil on the bottom of the pistons, quite useful in keeping these little round things intact.

The IHI (Ishikawajima-Harima Industries) turbo was mounted close to the electronic fuel injectors, which were just beyond the butterfly valve, and the blast of pressurized air would jam that fuel right into those combustion chambers. Where, in the interests of longevity, the compression ratios had been drastically lowered, from the 9.5:1 of the E and G to 7.4:1. The turbo had a non-adjustable pressure gauge and when the boost went over 9.6 psi the waste gate would open. The electronic ignition also had an ability to read boost pressures, retarding timing as the boost mounted. And should that waste gate get stuck, the ignition could deal with that as well. Pretty smart device. When the turbo began to intrude around 5,000 rpm, the lag was noticeable, but less than on the competition.

1983 Suzuki XN85D Turbo

The real trick with this XN85 was not so much the engine, but the chassis. The main frame was a round-tube double-cradle affair, with a triangulated backbone running to the steering head. Up front was a 37mm Kayaba fork, with anti-dive and air-adjustability, providing 5.5 inches of travel. Rake was a conservative 27 degrees, with trail of 3.9 inches. The fork connected to a 16-inch front wheel – which surprised many. Sixteen inches?! That was racing stuff. But even with a pretty lengthy 58.7 inches between axles, the bike handled extremely well. Probably helped along by the Full-Floater rear suspension, using an aluminum swingarm with caged needle bearings, the single Kayaba shock having remote hydraulic preload adjustment. And 4.1 inches of travel.

1983 Suzuki XN85D Turbo

The front wheel was endowed with a pair of 10-inch discs and single-piston calipers, while the rear wheel, a 17-incher, had an 11-inch disc with a single-piston caliper. They sound a bit iffy when compared to today’s GSX-R650 with radially mounted monoblock brakes, but the XN85 is 36 years in the past.

The half fairing looked great, and did a good job of protecting the rider if he wished to exceed the government-mandated 55-mph speed limit. The seat, 30.5 inches above the ground, was comfy, and the flat handlebar allowed for a cheerful 200-mile range – which was about what the five-gallon tank allowed. The fairing did disguise the fact that a modified version of the Ram Air System served to help cool the cylinders; the new design did not look at all like the RAS on the two-stroke triples in the 1970s.

Somehow the Turbo’s curb weight had shot up 70 pounds over the previous E model, weighing in at 550 pounds.

According to numbers found on the Internet, the factory produced only 1,153 of these turbos from 1983 to 1985, of which 300 in the first batch came to the United States. And sold at $4,700. A good reason for that was the third iteration of Suzuki’s normally-aspirated 750 four, which also came out in 1983, now with four valves per cylinder and Full-Floater rear suspension. It put out 72 horsepower at the rear wheel, weighed 30 pounds less than the Turbo and cost a mere $3,500. Talk about trumping your own ace!

Obviously the remaining 853 turbos were sold in motorcycling hotspots like Mongolia and Libya, in case you are looking for a used one.

Source: RiderMagazine.com

Retrospective: 1960-1964 Tohatsu CA2 Runpet Sport 50cc

1962 Tohatsu Runpet Sport 50cc
1962 Tohatsu Runpet Sport 50cc. Owner: Cliff Shoening, Bremerton, Washington.

This little charmer was in the first wave of Japanese bikes to enter the U.S. market, thanks to Hap Jones, a motorcycle racer and businessman of considerable note. Hap had been selling British bikes in the 1950s, and then decided to get out of the retail business, focusing on his more profitable distribution side. And the Japanese manufacturers were just getting interested in American buying habits, with Honda opening up for business in 1959, Yamaha in 1960.

So Hap got on the phone to Japan in 1961 and had a chat with the Tohatsu suits, who were undoubtedly very happy at the thought of getting into the burgeoning U.S. market, especially with a well-known and highly respected gent like Hap Jones. They arranged for a couple of 50cc Runpet models and several 125s to be sent over, a deal was struck and Hap introduced them to the world with a full-page ad in the January 1962 issue of “Cycle” magazine…quite unusual for a start-up to spend that kind of money. Then he had the good fortune to have a rider on a Tohatsu 125 win the lightweight Sportsman road race at Daytona, which gave him great publicity. Within a few months he claimed to have 300 motorcycle dealers and a number of sporting-goods stores carrying the Tohatsu line.

What was this little Runpet Sport? And this Tohatsu Company? The word is a combination of Tokyo and “hatsudoki” (engine factory), the origins going back to 1922 and the Takata Motor Research Corp., which made its reputation by building a small motor for a highly successful rail-track car. The name was changed to Tohatsu in 1939, and the company became focused on producing military equipment, including small motors to run little generators. War came and went, the factory survived, and it began selling these little motors to other companies building motorized bicycles. “Heck, we can do that ourselves,” some executive said, and Tohatsu began selling kits for bicycle owners to mount themselves, with gas tank, exhaust system and bracketry.

1962 Tohatsu Runpet Sport 50cc
1962 Tohatsu Runpet Sport 50cc. Owner: Cliff Shoening, Bremerton, Washington.

Better yet, it would build a sturdy bicycle, with a telescopic fork. In 1953 the Puppy appeared, powered by a 58cc two-stroke. Not a very attractive vehicle, but mildly efficient. In the mid-’50s the Japanese were all desirous of personal transportation and some 80 companies were competing in the motorized two-wheeler market. By 1956 Tohatsu was the biggest of the lot, selling 70,000 motorbikes, twice the number that Honda was. But competition was getting fierce, and the serious outfits like Honda, Yamaha and Bridgestone were busy modernizing their products, while dozens of the small operations were shutting down. Unfortunately Tohatsu’s success was followed by some major financial mismanagement, with lots of borrowing going on to keep the company afloat. In 1960 the government, through something called the Rehabilitation Act, arranged for Tohatsu to be bought by the Fuji Electric Manufacturing Corporation, the presumption being that this larger concern might be able to get Tohatsu back on its financial feet.

Motorcycles were just a part of the Tohatsu Company, with marine hardware, from bilge pumps to outboard motors, being more important. However, the two-wheeler R&D boys had been hard at work with new models now at hand, including the 50cc Runpets, the Japanese advertising saying in translation, “…with the accent on having fun!”

1962 Tohatsu Runpet Sport 50cc
1962 Tohatsu Runpet Sport 50cc. Owner: Cliff Shoening, Bremerton, Washington.

The Runpet Sport was indeed a sporty creature, with a highly tuned 49cc piston-port engine, fed through a TK carburetor that, like the Amals of the day, had both a tickler and a choke. A single-disc clutch connected to a three-speed gearbox. The factory claimed it put out 6.8 horsepower at 10,800 rpm and was capable of speeds in excess of 60 mph. Quite astounding for a street-worthy little single! It should be noted that 50cc racing was quite popular back then, especially in Japan.

Unfortunately Tohatsu did not get into developing automatic oiling, and owners had to do things the un-fun way, mixing the oil with the gas. As well as kickstarting the tiny terror. Tohatsu had put an electric starter on its basic Runpet with a lower state of tune, intended for the commuter and housewife, but the Sport was to live up to its name.

Chassis was simple, with a large tubular steel backbone frame from which the engine hung, two bolts securing the head; two more were down at the back close to the swingarm pivot. A telescopic fork up front. Two pairs of arms went back from the main frame to hold the saddle and places for bolting the tops of the two shock absorbers.

1962 Tohatsu Runpet Sport 50cc
1962 Tohatsu Runpet Sport 50cc. Owner: Cliff Shoening, Bremerton, Washington.

The 17-inch wheels had drum brakes, and the distance between axles was 44.5 inches. A 100 mph speedometer (rather optimistic) sat in the headlight nacelle, and a very small windshield served to enhance the sport look. A short saddle and no passenger pegs indicated that this was a one-up ride. But you could get the groceries, as there was a small luggage rack and two tiny pannier bags, made from the hide of a Nauga. Total weight was 135 pounds.

There were several options as to presentation, and this one has the scramblerish high pipe and small skid plate. Shiny chrome fenders and nice paint on the tank and side panels enhanced the image. The company was also putting out new two-stroke models, designed with American riders in mind, like a 125 parallel twin with four gears and 15 horsepower.

All to no avail. Bankruptcy was declared in 1964 and the motorcycle side was shut down. We don’t know how many Runpet Sports were sold by the 300 dealers Hap Jones claimed were carrying the brand, but there don’t seem to be many in the used-bike lists.

1962 Tohatsu Runpet Sport 50cc
1962 Tohatsu Runpet Sport 50cc. Owner: Cliff Shoening, Bremerton, Washington.

Source: RiderMagazine.com

Retrospective: 1974-1979 Kawasaki KZ400 Twin

1976 Kawasaki KZ400
1976 Kawasaki KZ400D3. Owner: Michael Lane, Kansas City, Kansas.

Nice little bike. Great for commuting, but entirely capable of a cross-country trip. This model was an answer to problems in the global economy. The dollar was devalued in 1971, with President Nixon taking us off the gold standard, meaning we had less money to spend on foreign products. Also, Congress was upping the import tariffs on lots of things, trying to figure out how to pay for the war in Vietnam. In response, Kawasaki decided to build a factory in Lincoln, Nebraska. This was not a real manufacturing facility, but more of an assembly plant, as the import duties on bits and pieces of a motorcycle were a lot less than bringing in a whole one.

1976 Kawasaki KZ400
1976 Kawasaki KZ400.

Kawasaki had been looking at the success of Honda’s little four-stroke twin, the CB350, which had modest performance but all the amenities Americans seemed to like, including an electric starter. Kawasaki’s R&D backroom boys put their heads together, drew up plans and came forth with a very efficient, if rather uninspired, 398cc vertical twin, with a 360-degree crankshaft, an overhead camshaft and an electric leg. In June of 1974 the first KZ400 rolled off the assembly line in Akashi, Japan, and a number of them arrived in the United States. But that was just the beginning, as the factory was turning out a lot more parts than those assembly line workers could use. Crates of them were going to Nebraska. In January of 1975 a KZ400 rolled off the Lincoln line with “Made in the USA” on the ID plate.

One should add that the price of gas went up 45 percent between 1973 and 1975, from 39 cents per gallon to 57 cents. Could there be a better time for a 50-mpg econo-bike to hit the market?

1976 Kawasaki KZ400
1976 Kawasaki KZ400.

The frame was a simple double cradle having dual downtubes, with a big, fat backbone tube meeting up with the cradle at the swingarm pivot, a very solid affair that avoided any notion of flexiness. Front fork was by Kawasaki, very much like a Ceriani, and on the inexpensive, non-adjustable side. Five inches of travel was good, with a 27-degree rake and trail of approximately four inches offering a very middle-of-the-road stance. The swingarm ran out 20 inches, bouncing along on a cheap pair of Kawasaki shock absorbers having preload adjustability and three inches of travel. Too soft, reviewers said.

Spoked wheels were both 18 inchers, the front carrying a 3.25 tire, the rear, 3.50. Braking was done by a single 226mm (10.91-inch) disc on the front, a 180mm (7.09-inch) drum on the back. As a polite reviewer might say, adequate. But this was not intended for sporting riding like the Z-1, and the brakes worked fine for commuter use. Distance between the axles was 53.3 inches.

The wet-sump engine was straightforward, being slightly oversquare with a 64mm bore, 62mm stroke. Of minor note was the chain-driven counter-rotating balancer system down in the crankcase, called “harmonic” by one reviewer. It did not smooth out all vibrations, but for anyone happy to ride at two-thirds of redline (9,000 rpm) it was entirely adequate. Commuters, the intended buyers, were not known as rip-snorting riders.

1976 Kawasaki KZ400
1976 Kawasaki KZ400.

The four valves, two per cylinder, were pushed down by a single overhead camshaft, and 36mm Keihin CV carbs fed high-test gas (preferred) and air into the combustion chambers, where it was compressed 9:1. The engine was rated by the factory at 35 ponies, which was usually measured at the crankshaft, not the rear wheel; on a dyno it was closer to 29. Respectable; good for an honest 90 mph. In 1977, with the fuel crisis in the headlines, the carb size was reduced to 32mm to enhance mileage figures a little. And the compression was raised to 9.4:1, which served to create roughly the same power output. Ignition was by battery and single two-feed coil. Starting was by button, except a kickstarter was there as a backup, as many Americans did not yet fully trust electrically powered gizmos.

1976 Kawasaki KZ400
1976 Kawasaki KZ400.

Primary drive was via a Hy-Vo chain, and then through a wet clutch to a five-speed transmission and chain final drive. The long, flat saddle was great for one person, a bit crowded for two. Looks were OK, with shiny chrome fenders and nice paint on the 3.2-gallon gas tank and side panels. Curb weight was a shade more than 400 pounds. The only complaint seemed to be about occasional oil weepage coming from around the head.

The number of KZ400 models expanded. The D series, the essential KZ400 that we have here, went from ’74 to ’77 and cost $1,170 in ’74. The cheaper S series, with a drum front brake and no electric starter, went for $995 in ’75. And for one year, ’77, there was the A model, with small handlebar fairing, saddlebags and luggage rack.

1976 Kawasaki KZ400
1976 Kawasaki KZ400.

For ’78 the D designation became a B, with a redesign in the head, a slightly different gas tank and mufflers, an extra gear in the transmission and the fuel tap getting a diaphragm. The low-price version stayed with five speeds and had a two-into-one exhaust. And there was the stepped-saddle LTD “custom” model, with cast wheels.

This modest motorcycle was also a modest financial success. Kawasaki ran a lot of entertaining ads focused on the commuter, one saying, “More fun than any car I ever drove.” This ’76 model, in the same family since new, is quite stock except for the MAC mufflers.

For 1980 the engine was bored out to 67.5 mm, a 10 percent increase in size, and received a new KZ440 designation, giving the basic design four more years of life.

Source: RiderMagazine.com

Retrospective: 1968-1973 Honda CL350 Scrambler

1968 Honda CL350 Scrambler
1968 Honda CL350 Scrambler. Owner: Jack Wagner, Grover Beach, California.

Honda motorcycles opened for business in the American market in 1959, when the four-stroke 50cc Super Cub came on the market. And over the next 10 years the company acquired a very positive reputation, well deserved, for having high revving, hard hitting, highly dependable products, especially with its 305 series, like the CB77 Super Hawk and CL77 Scrambler.

But, as we say about horses, the 305s were getting a bit long in the tooth. What to do? Shouldn’t cost too much because lots of money was going into the carefully kept secret–the four-cylinder CB750. Having a different number would be good, from 305 to 350. The bore was increased from 60 to 64mm, the stroke reduced from 54 to 50.6mm, the true size of the “new” engine being only 325cc. No matter, as minor exaggeration is considered to be quite acceptable in the advertising world.

Honda used it in three models, the 1968 CB Super Sport and CL Scrambler, and a year later the SL Motorsport. All told, more than 600,000 of these 350s were sold in the U.S. over the six years of production, which means a lot of them are probably still stashed in old barns or forgotten behind the junk in the back of the garage. Here we are dealing with the Scrambler version, better characterized as a street-scrambler, having only minor pretensions to being competent off the pavement. It was a styling thing, much like the “adventure” bikes of today, with the rider liking to think that he can dash across the Gobi Desert any time he wants. Or, more likely, he wants other people to think that.

1968 Honda CL350 Scrambler
1968 Honda CL350 Scrambler. Owner: Jack Wagner, Grover Beach, California.

The essence of the scrambler style were those upswept pipes, curving individually around the left side of the cylinders and ending up in one large muffler that held a permanent spark arrester. Which was covered by a black heat shield for the first two years, and then the shield was chromed. Interestingly, the shiny header pipes were pipes within pipes, the ostensible reason being that the owner would not have to put up with the inevitable bluing that arrived with time. A secondary reason, which should really be the primary, was that the actual pipes carrying the exhaust were quite small in order to maintain a high exhaust-gas velocity that was essential to the tuning system.

This whole CL exhaust shebang weighed a substantial 24 pounds, and was responsible for a loss of several horsepower compared to its CB sibling, which had a longer, more efficient exhaust. Power was 33 horses at 9,500 rpm in the CL, compared to the CB’s 36 at 10,500, despite the engine internals being identical. CL owners usually ignored the redline on the tachometer dial.

1968 Honda CL350 Scrambler
1968 Honda CL350 Scrambler. Owner: Jack Wagner, Grover Beach, California.

Another Scrambler notion was the larger front wheel, 19 inches as opposed to 18. This was more about looks than performance, with the more serious off-roader, the SL, having a 21-incher. Front fender was slightly abbreviated, and the gas tank held 2.4 gallons, almost a gallon less than the CB’s. There were also rubber gaiters on the CL’s fork legs, always good for the daredevil look.

Those were the differences, now for the similarities. Looking into the powertrain, the parallel twin used alloy cylinders with iron liners, and the oversquare engine had lots of possibilities for revs–10,500 of them! In 1968 street-going four-strokes were not known for spinning ten thousand times a minute, and the less knowledgeable thought that this would mean a brief lifespan. But ten grand! How did they achieve that? First, there was a single overhead camshaft, spun by an endless chain between the cylinders. And the camshaft itself was a solid piece of work, weighing some three pounds.

1968 Honda CL350 Scrambler
1968 Honda CL350 Scrambler. Owner: Jack Wagner, Grover Beach, California.

But how does one get valves to seat properly at that speed? The valves all had dual coil springs, but the springs themselves were wound progressively, so that there was relatively less tension when the valve was seated, increasing greatly as the valve got pushed down. Carburetion was a pair of 26mm Keihin constant-velocity units using neoprene diaphragms.

The crankshaft, with four main bearings, spun using a 180-degree firing order as on the 305, but was a lot smoother due to excellent balancing. Primary drive was via straight-cut “paired” gears that were both efficient and quiet. Honda knew that the popular helical gears were quiet but not overly efficient, and came up with this mildly complicated system. A multi-disc wet clutch passed power through a five-speed transmission (up a gear from the 305) and out via a chain running along the left side of the rear wheel.

The chassis was not a notable construction, but suitable for delivering a good feeling to the rider. The backbone was a pressed-steel stamping, which was falling out of aesthetic favor at the time, though inexpensive to make. Fortunately it was hidden beneath the gas tank, and the viewable bits were mostly tubular, a single tube coming down from the steering head to spread into a double cradle.

1968 Honda CL350 Scrambler
1968 Honda CL350 Scrambler. Owner: Jack Wagner, Grover Beach, California.

Suspension was adequate, with a telescoping fork at the front and a pair of DeCarbon-type shocks at the back. A 3.00-19 tire was on the front wheel, 3.50-18 at the back. A double-leading shoe drum brake did yeoman’s service at the front, a single leading shoe at the back. It had 52 inches between the axles, and a wet weight of around 370 pounds.

The saddle, about 32 inches high, was long and flat, while the upswept handlebars had the mandatory cross-brace, part of the scrambler look. The rider saw separate speedo and tach above the headlight. Fenders were chromed, with excellent paint on the gas tank and side panels. And the essential electric leg for starting.

Price was $700, less than half that of the 750 four. Which is why these middling bikes outsold the big one…though we can only presume that quite a few 350 owners upgraded to the 750.

Source: RiderMagazine.com

Retrospective: 1969-1971 Yamaha DS6-C 250cc Street Scrambler

1969 Yamaha DS6-C Street Scrambler. Owner: Ed Heckman, Paso Robles, California.
1969 Yamaha DS6-C Street Scrambler. Owner: Ed Heckman, Paso Robles, California.

For more than 10 years 250 two-stroke twins were the mainstay of the Yamaha range here in the United States, from the DS1 of 1959 (though not sold in the U.S. until 1961) to the DS7 of 1972. We have no idea what the DS stands for, but doubt that it has anything to do with the DS prefix used in Yamaha’s music department. Two-strokes were the popular engines for sporty bikes in the 1960s, being reasonably powerful and inexpensive to make. Running against this 250 DS6 were Suzuki’s Hustler and Kawasaki’s Samurai, all in the $600 range. Any college student having a few bucks in his pocket could probably arrange time payments with the local dealer…backed by Dad’s signature.

When Yamaha advertised this quarter-liter as having 30 horsepower, interest was great. And it passed the eye test as well, with high pipes, one on each side. This was styled as a dual-purpose machine–hence the C in the alpha numerology. The chassis design was much more favorable to the street rather than the trail, so the high pipes were more a styling point rather than functional.

1969 Yamaha DS6-C Street Scrambler. Owner: Ed Heckman, Paso Robles, California.The history of the DS6 engine was long and had the distinct advantage of being associated with Yamaha’s racing 250, the TD1, which had great success over the previous decade. Riders could thank Yamaha’s racing shop for improvements, as the company was intent on keeping its 250 riders on the podium. And what is good on the track can be tuned down to find its place on the street. Any time the engineers improved the racer, they would try to figure out a way to adapt whatever it was to the street bike. Ads for the DS6 promoted the TD’s Daytona wins in 1967 and 1968.

The DS6 246cc engine was of piston-port design, with the 56mm bore and 50mm stroke that had been around for 10 years. This was a genuine five-porter, the ports being cast into the aluminum cylinders with cast iron liners. The new for ’69 cylinders had three transfer ports, along with intake and exhaust, allowing for a larger fuel charge to find its way into the combustion chambers faster. Compression ratio was a reliable 7.3:1, and the cylinders now had copper head gaskets to replace the earlier aluminum ones–which had a tendency to fail when pushed very hard. Naturally these new gaskets came from the racing TDs. Inside the engine were race-worthy bearings, though they would never be subjected to the 10,000-plus rpm attained by TDs. Those 30 advertised horses were said to be generated at 7,500 rpm, and were certainly taken off the crankshaft rather than the rear wheel. Road tests merely quoted the “claimed bhp.”

1969 Yamaha DS6-C Street Scrambler. Owner: Ed Heckman, Paso Robles, California.Two 26mm Mikuni VMC two-stroke carbs combined with Yamaha’s Autolube system fed the fuel/oil mixture into the crankcase. Yamaha was noted for having developed the Autolube system, using a separate container for oil rather than messily mixing it with gas in the tank. It was being used on Yamaha’s race bikes in the late ’50s, and then adapted to street machines in the early ’60s. The greatest advantage to Autolube was that it could closely regulate the amount of oil to be mixed with the gas, so instead of having a steady 20:l mixture, which could get quite smoky at times, the oil was metered by both engine speed and the opening of the throttle valves. This could diminish oil input when idling through town, and give it an almighty whack when the rider decided that a full-on accelerator rush down a country road was in order. The oil capacity was three pints, which was good for half a dozen fill-ups of the 3-gallon gas tank.

1969 Yamaha DS6-C Street Scrambler. Owner: Ed Heckman, Paso Robles, California.Crankshaft power ran back the left side via helical gears to a seven plate clutch, blessed with six torsion springs that helped to absorb even the most abrupt of gear changes. And rubber cushions in the hub helped reduce vibration. Smoothness was what the rider felt when going through the five gears. All this sat securely in a tubular steel double-cradle frame, which looked remarkably like that on a race bike.

A rather steep 34mm telescopic fork ran down to the 18-inch front wheel, where a 7-inch double-leading-shoe front brake did an excellent job of slowing things down. The rear swingarm had a pair of shocks with adjustments available for spring preload. And the wheel, another 18-incher, also had a 7-inch brake, but with a single leading shoe. The 50.8-inch wheelbase was a quick handler on the street, but would keep the sensible trail rider at a more modest pace.

1969 Yamaha DS6-C Street Scrambler. Owner: Ed Heckman, Paso Robles, California.The look was quite different from the preceding low-pipe DS5, which had a rather bulbous 4-gallon tank, and speedometer and tach built into one unit. The smaller 3-gallon teardrop tank was much more attractive in appearance, and the speedo and tach were now separate…very English. Long, flat saddle and chromed metal fenders added to the good looks, going along with the upswept pipes–which did have protective heat-shielding, but long pants were advisable. Yamaha had dropped a tooth from the DS5 countershaft sprocket, which reduced the top speed a small amount, down to 90 or so mph–depending on the weight sitting on the saddle. And a skid plate was bolted on, more for looks than the thought that this shiny fellow would ever scrape its underbelly.

The DS6-C weight was down 20 pounds on DS5, weighing 304 pounds dry. Much of that had to do with the absence of an electric starter. Firing up this baby was done the old-fashioned way…admittedly a very simple task.

The DS series was a great sales success, lasting until the RD250s took over in 1973.

1969 Yamaha DS6-C Street Scrambler. Owner: Ed Heckman, Paso Robles, California.

1969 Yamaha DS6-C Street Scrambler. Owner: Ed Heckman, Paso Robles, California.

Source: RiderMagazine.com

Retrospective: 1956-1962 Norton Dominator 99 600cc

1958 Norton Dominator 99. Owner: Cliff Schoening. Photos by Ralph Noble.
1958 Norton Dominator 99. Owner: Cliff Schoening. Photos by Ralph Noble.

This was the bike that got a lot of Americans excited about the Norton marque. Brit bikes were relatively rare in the U.S. in the early 1950s, with mainly Triumph and BSA battling it out. Yanks had long read about Norton’s racing successes, like when a 500 Manx came in second at Daytona in 1949, but were not much interested in the single-cylinder Internationals, civilianized versions of the racing Manx. What they wanted was an easy to start twin, with enough zip to run up to the semi-magical 100 mph mark. The 500cc Dominator 88 did not quite have the punch needed, but when it was bored and stroked to 600cc (actually 597cc), that stoked some serious interest.

Some people, both industry and consumers, were a little surprised that Norton had not gone to the popular 650 size, which Triumph had done in 1950 with the Thunderbird, and BSA a year later with the Golden Flash. Nortons began to be imported in 1949, and had six U.S. distributors. After the arrival of the 99 the distributors apparently got together and jointly bought the first full-page ad seen in the bike magazines–in the November ’66 “Cycle.” After a very complimentary road test in the September issue.

1958 Norton Dominator 99Norton was an old company, with James Lansdowne Norton founding the Norton Manufacturing Company at the age of 29, back in 1898, when it started manufacturing chains for the burgeoning bicycle market. But motorized bicycles were the coming thing, and JLN got right on it. His 690cc Peugeot-powered V-twin, a touring model, won the Isle of Man Tourist Trophy in 1907; success was clearly in the stars. Norton began building its own engines and prospered.

Late in 1945, after WWII, Norton went back to building civilian motorcycles, both a side valve and an OHV 500 single, along with a very few OHC 350 and 500 Internationals. Triumph was hitting the advertising pages big time, promoting its sleek T100 Tiger 500cc twin, and that was getting a lot of attention. So Norton did the logical thing and hired a designer named Bert Hopwood, who had worked at Triumph before the war when the T100 first came to light. He joined Norton in 1947, improved the singles, and then worked on developing a parallel twin. In November of 1948 the Dominator Model 7 showed up at the annual Earl’s Court motorcycle show, with a vertical twin engine mounted in a Norton frame with a telescopic fork and a plunger rear suspension. Unfortunately, at 440 pounds it was 75 pounds heavier than the Triumph. In 1949 Hopwood moved on to the BSA company, assigned to the task of making BSA’s 500 twin into a 650.

1958 Norton Dominator 99Norton went to work bringing the Dominator 7’s weight down, and the big innovation was the advent of the Featherbed frame, originally intended for the racing Manxes. Previous frames had been complicated and heavy, whereas the Featherbed was essentially two one-piece loops that was both lighter and stronger, using expensive Reynolds 531 manganese-molybdenum, mild-carbon steel tubing. Since everything passes through the steering head, the backbone tubes were welded to the bottom of the head, while the downtubes actually ran between the backbone tubes and then welded to the top of the head. All suitably braced.

Norton then went about making a roadster edition of the frame, using less expensive steel. Initially the saddle-supporting rear section was bolted on, but soon was welded, as that was a lighter approach. Norton also saw fit to give the frame its own name, plus a secondary description, which began with Wideline, and then Slimline (1960), referring to the width of the frame beneath the forward part of the saddle. The 99 used an oil-damped Roadholder fork and a swingarm rear end with a pair of Girling shock absorbers. When the 500 Domi 7 twin got the Featherbed, the bike received new numeration: Domi 88.

1958 Norton Dominator 99Move forward to 1955, and we find Mr. Hopwood being invited to rejoin the Norton Company. And soon the 497cc 88 had a larger sibling, the 597cc 99, the 100cc gained by using an even longer stroke…the 88 having a 66 x 72.6mm bore and stroke, the 99, 66 x 82mm.

Nothing exceptional about the dry-sump engine. The crankcase was split vertically, the cylinders were iron, the head aluminum alloy. The camshaft was up at the front of the engine with four light-alloy pushrods operating the four valves. A single Amal Monobloc fed the fuel to the combustion chamber, having a modest compression ratio of 7.6:1.

A single-row primary chain ran in an oil bath from the crank to clutch, which had little rubber shock absorbers. This was all done inside a sheet-metal primary case. And if the cork gasket was in good shape, the oil stayed inside. The four-speed transmission was made by Norton, and in best British tradition, the shift was on the right side, up for first.

1958 Norton Dominator 99The bike weighed some 410 pounds wet, and put out 31 horsepower. It had a comfortable seat, slightly Americanized handlebars and a 4.4-gallon tank–test write-ups said the 99 got more than 50 mpg. The headlight shell held a speedometer, ammeter and light switch. Initially a Lucas magneto sparked the plugs and a dynamo lit the seven-inch headlight, but in 1958 a crankshaft-driven alternator and distributor did both tasks. Petcock on, choke if cold, tickle the carb, fold out the starter and a healthy kick or two would get the engine going.

That “Cycle” road test reported a top speed of 114 mph–impressive. And a quarter-mile time of 14.61 seconds. Equally impressive.

The years went on. In 1961 the 99SS version appeared, with twin carbs. Last official year for the 99 and 99SS was 1962, replaced by the 650SS, now stroked to 89mm to get the additional 50cc.

Source: RiderMagazine.com

Retrospective: 1974-1977 Montesa Cota 247-T

1977 Montesa Cota 247-T
1977 Montesa Cota 247-T. Owner: Pete Gray, Atascadero, California.

The Spanish Civil War ended in 1939, and then the rest of Europe spun out of control. Spain sensibly decided to stay neutral in World War II. With a limited domestic market, business stagnated. But by 1944, with the end of that conflict in sight, Spaniards started thinking about the future. A couple of like-minded fellows, Pedro Permanyer and Francisco Bulto, met up and decided that providing their countrymen with basic transportation could be profitable. They built a factory in Barcelona and began producing Montesa motorcycles, little two-stroke singles under 125cc, and had great success. But the partners had their differences, and in 1958 Bulto went off on his own to found the Bultaco motorcycle company.

Permanyer persisted, built larger engines, and in 1965 showed the 247cc engine (21 horsepower at 7,000 rpm) in a Scorpion motocrosser. Several years later a mildly detuned version appeared in the Cota trials bike, and in 1968 the Cota won the Spanish Trials Championship. It should be noted that trials competitions were very popular in Europe, less so in the U.S.

1977 Montesa Cota 247-TIn the early 1970s the Japanese OEMs began modifying some of their competitive 250 dirt models into more civilized trail bikes, or as we might say today, dual-purpose. These had two-up seats, lights, a horn, whatever it took to make them street-legal. Permanyer took note. He had a great 250 engine, seen in motocross, roadracing, enduro and trials versions, so why not turn that trials bike into a trail version for the European street crowd; those countries weren’t quite as fearful of two-stroke emissions as were the Americans. The Cota 247-T (for Trail) was born.

Montesa had about 300 dealers in the U.S., who were doing well with some of the competition bikes. Apparently the importer thought this 247-T could be an added attraction. According to sketchy records the factory produced some 2,300 of them, with very few coming to this country. One reason being that it was expensive compared to the competition.

1977 Montesa Cota 247-TThe Owner’s Manual, in Spanish, English and French, begins well: “The MONTESA motorcycle which model is introduced here do (sic) not require an excessive care for maintenance, only a minimum attention is required to ensure a long and perfect serviceable time.” Truth, as the Cota is a delightfully basic machine.

The oversquare piston-port single cylinder has a bore of 72.5mm, stroke, 60mm, with a compression ratio of 10 to 1, generating some 19 horsepower at 6,500 rpm. Ignition is via a flywheel magneto/alternator and coil. The header pipe goes out the left side, high up, with a two-part muffler and spark arrestor. A respectable muffler, too, the two-stroke pop-pop being pleasantly muted.

The air cleaner is under the seat, with a Spanish-made 27mm Amal carburetor carrying fuel into the engine. A previous owner of this bike has replaced the Amal with a Mikuni. Should there be a need to remove the carb, the manual says, “Have in mind that you must shut the entrance of the admission pipe while the carburetor is out, in order to avoid the entrance of odd objects in the interior of the cylinder.”

1977 Montesa Cota 247-TPrimary drive is via spur gears, 22 teeth off the crankshaft, 64 teeth on the clutch, which uses “multiple steel discs in oil bath with constant tension springs….” That power goes through a five-speed transmission to a 10-tooth countershaft sprocket and a 40-toother on the back wheel. A very nifty chain-oiler has been built into the right arm of the swingarm, which holds a supply of oil that drips onto the chain just as it enters a tensioning device.

The engine/transmission unit sits in a tubular steel frame, with bolts holding it steady fore, aft and top. A single tube comes down from the reinforced steering head, spreading into a cradle at the front of the crankcase, with a sturdy skid plate built in. A small hole in the skid plate allows access to the drain plug. The rear section, holding the seat and upper shock absorber mounts, is built into the main frame, with a strong pivot point for the swingarm. The shocks on this model have no identification mark, but are probably of Telesco making. The telescoping fork is Montesa-made, with a 29.5-degree rake, 5.6 inches of trail.

A 21-inch wheel at the front wears a 2.75 tire, an 18-incher at the back has a 4.00 tire. Small 110mm single-leading-shoe full-width drum brakes are at both ends. When inspecting the wheels it is advisable “to slightly grease all the whirling points with SAE-40 oil.” A short 51.5 inches lie between the axles.

1977 Montesa Cota 247-TThe bike has an attractively slim look, having a narrow 2.14-gallon fiberglass gas tank with wings extending under the long saddle. Fenders are lightweight alloy. A small headlight, horn and taillight make it more or less roadworthy, except there is no battery. The speedometer is missing from the photo model. A modest toolkit fits into a cylindrical container beneath the seat. Dry weight, according to the manual, is 200 pounds…lightweight fun!

The last 247cc 247-T was built in 1977, the similarly branded 1978 version having a slightly smaller 237cc engine. That model was then dropped, but the 348-T version kept on for two more years.

Postscript: In 1980 a trials version, the Cota 348, won the World Trials Championship, but Montesa was running into serious financial difficulties. The next year Honda essentially bought the company in order to have better access to the European market, and Montesa Cota models are still being built–albeit with four-stroke engines.

Source: RiderMagazine.com