Sonic Boom: 1982 Can-Am Sonic 500

The Can-Am Sonic 500 wasn’t a big seller when it was built, making it a rare model today.

Sonic 500

1982 Can-Am Sonic 500.

Photo by Robert Smith

Content Tools

1982 Can-Am Sonic 500
Engine:
494cc air-cooled SOHC single, 89mm x 79.4mm bore and stroke, 9.2:1 compression ratio, 37hp @ 7,000rpm
Top speed:
NA
Carburetion:
Single Mikuni VM36
Transmission:
5-speed, chain final drive
Electrics:
12v, CDI electronic ignition
Frame/wheelbase:
Single downtube dual cradle 4130 chrome-moly steel tube w/oil-bearing spine/58.5in (1,486mm)
Suspension:
42mm Marzocchi telescopic forks front, dual Öhlins shocks rear
Brakes:
6in (152.4mm) SLS drum front and rear
Tires:
3 x 21in front, 5.10 x 18in rear
Weight (dry):
269lb (122kg)
Seat height (stock)
: 36in (914.4mm)
Fuel capacity/MPG:
2.8gal (10.6ltr)/NA
Price then/Now:
$3,000 (approx.)/$3,500-$6,500

More than a few motorcycle manufacturers have diversified into snowmobiles and other recreational products to make their business less seasonal. Ski-Doo maker Bombardier did it the other way around.

Joseph-Armand Bombardier was born in 1907 in Valcourt, an eastern township of Quebec, Canada. Always interested in mechanics, at age 19 he opened an automobile repair shop. One of his first challenges was that Quebec’s brutal, snowy winters kept most motorists off the road in winter, making for plenty of downtime. Only main highways were plowed, so many drivers stored their cars away for the season.

It was a personal tragedy that provided the incentive for Bombardier’s first product. One particularly bad winter, his young son fell ill. Because of the heavy snow accumulation on the roads, he was unable to transport his son to the hospital. As a result, his son died.

Bombardier’s first snow-car design was the model B7 of 1936. Powered by a 4-cylinder Chevrolet engine, it was essentially a seven-passenger car with tracks at the rear to provide drive and skids at the front for steering. It was so successful that a larger vehicle, the 12-passenger B12 Snowbus, soon followed. By 1940, the company was installed in a purpose-built facility and was producing 200 vehicles a year.

During World War II, Bombardier turned to making equipment for the Canadian military, but resumed civilian production in the late 1940s. A new policy in 1948 from the Quebec government introduced more widespread snow plowing, which changed Bombardier’s direction. With winter roads more accessible, sales of the multi-passenger tracked vehicles declined. Bombardier turned to the burgeoning winter recreation market instead, designing a much smaller single-tracked vehicle with external seating for one or two people. He called it the Ski-Doo.

The Ski-Doo was launched in 1959, and just 200 units sold that year, but by the time of Bombardier’s death in 1964 the idea had caught on, with more than 8,000 Ski-Doos sold annually. By this time, other manufacturers, especially Polaris, had entered the market, and competition was getting fierce.

Meanwhile, by 1962 proprietary engine manufacturer Rotax-Werk AG of Gunskirchen, Austria, had begun supplying engines to Bombardier for use in its Ski-Doos. To secure its supply of engines, and also to facilitate its next change of direction, in 1970 Bombardier purchased Rotax, with the Austrian company operating as Bombardier-Rotax GmbH. With more companies entering the market, and with its core business being highly seasonal, Bombardier decided to diversify.

Building motorcycles

In 1970, Bombardier hired American Gary Robison as director of motorcycle research and development for its new Can-Am motorcycle division. He was soon joined by two-time motocross world champion Jeff Smith, and they began, along with a team of technicians from both sides of the border, to develop motocross and enduro bikes based on a new line of rotary-valve 2-stroke Rotax engines.

The advantage of a rotary intake valve is the ability of tuners to vary the induction timing for different power characteristics. Vespa had used a rotary valve in many of its scooters from the late 1950s, but the goal had been fuel efficiency rather than power. Bridgestone and Kawasaki had also produced rotary-valve 2-strokes, but with the focus more on output. Rotax’s innovation was to mount the carburetor behind the engine rather than on the side. This reduced the width of the engine at the cost of a longer intake tract. Rotax produced two versions of the engine with different power characteristics for motocross and enduro, the MX-1 and TnT. Both were available in 125cc and 175cc versions.

The Rotax engine pioneered many 2-stroke technologies, like Nikasil-plated cylinders and triple exhaust ports. It also produced impressive power: With 13:1 compression, the 125cc version claimed 20 horsepower at 9,500rpm, with 25 horsepower at 8,500rpm for the 175cc. Oil was fed directly to the crankshaft by a pump, and the engine was mated to a 6-speed transmission.

The power unit fitted into a triangulated, dual-cradle steel tube frame with a tapered, large-diameter spine that held the engine oil. The rear swingarm pivot was located by frame plates and also formed the rear engine mount, ensuring strength and rigidity while improving drive chain geometry. The front fork was by Betor, but with a Can-Am innovation: From the triple trees, the steering angle was adjustable through six degrees to suit track conditions and rider preference. Nine-way adjustable Girling spring/shock units controlled the rear wheel. Wheels were 3 x 21 inches front and 4 x 18 inches rear with Sun alloy rims, and the fenders and gas tank were formed from memory-tempered high-density polyethylene, which Bombardier claimed were “virtually indestructible.”

Combining high power with quick handling, the TnT enduro version competed in the 1973 International Six Days Trial, with riders winning Gold, Silver and Bronze medals. In 1974, Can-Am introduced a 5-speed, 33 horsepower 250cc version, becoming the first brand to sweep the AMA 250cc motocross national championship, with riders Gary Jones, Marty Tripes and Jimmy Ellis finishing first, second and third. Can-Am rider Skip Olson also finished second to Dick Burleson in the 1976 AMA Enduro National Championship.

Also in 1976, Can-Am announced a major revision with the MX-3. It followed the contemporary fashion for laid-down rear shocks and greater fork travel, using a new Marzocchi front end. With a class-leading 36 horsepower, the MX-3 250 became notorious for being almost unrideable because of its vicious powerband and nervous handling, earning the nickname “Black Widow.”

Beginnings of the 500

In 1980, Cycle World magazine chose the MX-6 as its 250cc bike of the year: “With the 250 MX-6, Can-Am has done more than hold their own against the market leaders. Yellow, red and green machines may dominate motocross start lines across the country — and maybe even finish lines — but not because they hold a performance advantage on the Can-Am. The MX-6 has the best engine in its class. It handles as well as any of the competitors and better than most. Its blemishes are few, the most serious being its tender clutch. If you decide to go with the orange machine, it will be an act of defiance, but it will be a calculated act with a predictable result: Winning.”

But by 1980, and with the dominance of Japanese 2-strokes in offroad competition, Can-Am realized it could no longer remain competitive. Neither could the team afford the extravagant salaries of the top riders of the day, so the MX-6 was the last Can-Am 2-stroke produced in quantity. But they had one last kick at the can. With enduro racing becoming more popular, and moves to ban or restrict 2-strokes in offroad competition, Can-Am co-opted the “in-house” 494cc single overhead cam Rotax Type 504 4-valve single and dropped it into a frame based on the MX-3. They used a Marzocchi front fork, but without the lay-down rear dual shocks, using the more upright type instead. The diamond-section alloy swingarm was controlled by dual Öhlins shocks, giving almost 12 inches of ground clearance. Though fitted with a minimal lighting system, the Sonic was not intended for road use. No speedometer was fitted (just a trip meter) and its short gearing was unsuitable for the street, and the spark-arrestor muffler made sure it would comply with U.S. offroad requirements. The Sonic was clearly intended for enduro use. Few were sold, however, making the example shown here (though not completely stock) extremely rare.

In the early 1980s, Bombardier’s attention was being drawn toward its railcar business, worth many times more than motorcycles. To satisfy their dealers’ need for summer sales, Bombardier moved into personal watercraft (the Sea-Doo) and quad bikes. Jeff Smith was let go in 1982, but the rights to the Can-Am motorcycle business were acquired by the British Armstrong company, whose CCM division produced a mil-spec motorcycle, the MT500, for British and European forces.

When Armstrong sold CCM in 1987, manufacture of the MT500 (but with a 350cc engine) went to Harley-Davidson in the U.S., becoming the MT350, which was standard equipment for the U.S. military and NATO until it was replaced by diesel-engined Kawasaki KLRs.

George Phillips’ Sonic 500

In sales training, they call it the puppy-dog close: You let your potential customer take the “puppy” home for the weekend. It rarely comes back. In this particular case, the salesman was Jon Shanks of Champion Cycle in Chilliwack, British Columbia, Canada. The customer was motocross racer George Phillips, now of Williams Lake, B.C., and the puppy was a brand-new 1982 Can-Am Sonic 500. First, though, Jon invited George to take it for a test ride.

“I thought, ‘Why not?’” George says. “So off to the mountains we go.” George admits the 500 took some getting used to: It was tall, with nearly 12 inches of ground clearance and a seat height of over 36 inches. In spite of the fact that George was over 6 feet tall, it was, he says “like mounting a horse.” And the kickstarter was on the left side. “Thank goodness for a decompressor!”

More used to the small Hodakas, Bultacos and Montesas of the day, George found the big Can-Am challenging. “This was the first time I’d ridden a 4-stroke dirt or enduro bike. The power band took a little getting used to, but it became a fun bike to ride. I got comfortable riding this bike — and maybe a little too confident. We were riding on Mount Thurston, which has a very steep climb, and I was so close to cresting the top … Need I say more?” George offered to repair the mostly cosmetic damage, but instead Jon invited him to keep the Sonic for the weekend. “He knew I was the only one who could handle this baby. I felt it was very good of him to trust me, so we made a deal. If my memory serves me right the purchase price was $1,700. A good deal I thought,” George says.

Making it right

After riding the Sonic for a while, George discovered its deficiencies. “It was not a good handling bike in the tight trails,” he says, adding, “It was just too tall.” George consulted mechanic friend Gord Hill, now owner of Chilliwack Motorcycles in Chilliwack, B.C., and they decided to make the off-highway-only Sonic street legal. “Gord put a lot of thought into the modifications,” George says.

First, they cut two inches off the rear coil springs, reducing the travel to 7-1/2 inches, and the kickstand was shortened to suit. The headlight was changed to a larger unit, the trip odometer was replaced with a proper speedometer, while a taillight, brake light, horn and mirror were also added. “We also changed the gearing to give it a little more top end for the highway,” George says. “It handles like a dream.”

George doesn’t ride as much as he once did, but he’s still enthusiastic about the offroad scene. “I have a lot of fond memories of those early years of motorcycling,” he says, yet adding, “I wish I was 20 years younger and riding the iron that’s on the market today. What a thrill it would be!” MC