Suck, Squeeze, Bang, Blow: 1978-1981 Yamaha SR500

A comparison of the Yamaha SR500 years 1978 to 1981 and the Royal Enfield Bullet 500 and the 1982-83 Honda FT500 Ascot.

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by Motorcycle Classics Archive
An original ad featuring the Yamaha SR500 touts its nostalgic styling.

Years produced: 1978-1981

Total production: 15,000 (est.)

Claimed power: 33hp @ 6,500rpm

Top speed: 96mph

Engine: SOHC, air-cooled, 4-stroke single, 87mm x 84mm bore and stroke, 5-speed

Weight (dry): 353lb (160kg)

Price then: $1,898 (1980)

Price now: $1,000-$3,000

MPG: 45-60

Most of today’s motorcycles insulate us from the sound of the 4-stroke cycle. A multitude of cylinders, liquid cooling and efficient muffling mean the characteristic tenor of Nicolaus Otto’s invention is often lost in the engine’s general thrum. But it wasn’t always thus. The best opportunity to hear Otto’s cycle at work is from an air-cooled, 4-stroke single, like a BSA Gold Star, Velocette Venom, Moto Guzzi single … or perhaps a Yamaha SR500.

Riding a one-lunger of 500cc or more, especially one that pre-dates (or scorns) balance shafts, can leave the rider with numb hands and blurred vision. And without an electric leg, kickstarting can be chancy and even injurious if you ignore the proper procedure. So why would anyone want a big 4-stroke single? Words like character, simplicity, authenticity, and feel are bandied around. By the 1970s, multi-cylinder machines had stifled the sound and diminished vibration: but for some, that just compromised the rider experience. So did Yamaha’s SR500 of 1978 harken back to earlier times; or was it a slick new interpretation of the classic formula? Maybe it was both.

Until the Seventies, Yamaha produced only 2-stroke motorcycles. But impending EPA restrictions meant a 4-stroke future; the 1970 XS-1 650, 1973 TX500 and TX750, and the TT500 of 1975 were the result. The TT500 was intended as a motocrosser along the lines of the lightweight European 4-strokes. But with 2-strokes dominating in the dirt, Yamaha repositioned it as a desert racer at which it excelled, placing first and second in the inaugural Paris-Dakar race in 1979 and taking the top four spots in 1980. By this time, the street-legal, dual sport XT500 was selling like hot cakes. How would the TT500 engine work in a pure street bike?

The 87mm x 84mm engine’s bottom end followed 2-stroke practice with a built-up crankshaft, caged roller big end and ball main bearings. A chain drove the single overhead camshaft. Lubrication was dry sump, with oil carried in the frame. Starting was kick only, and there was no balance shaft.

Launched in 1978 with electronic ignition, the SR also had a heavier crank, larger valves and more cooling fin area than the XT. The drivetrain slotted into a half-duplex steel tube frame running on 3.50 x 19-inch front and 4.00 x 18-inch rear cast alloy wheels, each with a single disc brake. A model revision for 1980 saw a drum brake replace the rear disc, together with a lighter crankshaft and EPA-required changes to the carburetor. The last SR500 imported to the U.S. was in 1981, though production continued until 1999 for Europe.

Testers had mixed feelings about kickstarting the SR, though some found it unexpectedly easy, thanks to a cunning user interface. A decompressor allows the crank to be turned to its optimal position, indicated by a tell-tale window on the cam box; a choke control facilitates cold starts; and a push-button sets the carburetor correctly for warm starts. Then a committed swing without touching the throttle usually works, according to period reports. “I seldom needed more than one or two pounces on the inoffensive kicklever to get things thumping,” wrote Road Rider.

And once on the road, praise was generous as riders enjoyed the instant throttle response, easy handling, light weight and simple operation. “For our testers who were familiar with those classic British singles, riding the uncomplicated, down to earth SR500 was like coming home again,” wrote Cycle Guide. “It’s an elemental machine that doesn’t try to hide the fact that it is a motorcycle. And that honesty alone is enough reason for the SR500 to exist.”

“The SR500 is a motorcycle for enthusiasts,” wrote Cycle World. “For those who accept the SR500 for what it is, the rewards are worth the effort. For them, this is the most satisfying bike on the market.” MC

Royal Enfield Bullet 500

Though not a contemporary of the SR and FT, the Bullet connects them to the big singles of the past — yet outlived both of them. The Bullet was groundbreaking in its day, pioneering swingarm frames and telescopic forks. Numerous successes at the International Six Days Trial attracted attention from the Indian army, which purchased them from the Redditch, U.K., company in the mid-1950s before acquiring a license to produce Bullets in Madras, India (now Chennai).

The 350cc Bullet stayed in production in either India or the U.K. for 55 years, while the 500 was produced in the U.K. from 1952-62 when the company was sold. Production of a 500cc Bullet started in India around 1988. The 500 provides a steady and stately ride, but with slogging hill-climbing ability. The engine feels lazy, the gearshift is heavy and slow, handling is solid, the later (twin-leading-shoe front) brakes are adequate. Kickstarting is straightforward using the ammeter as a tell-tale to find TDC. Electric start appeared with the Electra model in 2004. The U.K. bikes were generally more durable than their Indian counterparts (mostly because of better metallurgy). Bullets, like most Enfields, use a twin-piston oil pump that needs to be checked regularly for wear, and frequent oil and filter changes are a must. Enfield parts are still readily available from Hitchcocks Motorcycles,

• Years produced: 1952-1962 (U.K.) and 1989-2007 (India)
• Engine: 499cc air-cooled OHV 4-stroke single, 84mm x 90mm bore and stroke, 4-speed
• Claimed power: 25hp @ 5,750rpm
• Top speed : 78mph
• Weight (wet): 420lb (191kg)
• MPG: 45-65 (est.)
• Price then/now: $600-$700/$2,500-$7,000

1982-1983 Honda FT500 Ascot

Honda’s otherwise similar half-liter single had two things the SR500 didn’t: electric start and a balance shaft. Ingenious though the SR500’s kickstarting aids were, they were no substitute for a button on the handlebar.

The Ascot engine was based on the 4-valve XL500 dual-sport, but added these aforementioned features. Like the SR, the FT500 engine used a caged roller big end, the crank running on a pair of ball main bearings with drive to the overhead camshaft by chain. And like the Yamaha it featured 19- and 18-inch cast alloy wheels with a single brake disc front and rear.

Although making similar horsepower, the Honda needed more revs to get into the powerband. Testers enjoyed the Ascot’s excellent handling and cornering clearance, which made up for its relatively slow straight-line performance. Steering was light and the brakes effective. Suspension was air-adjustable at the front, with five settings at the rear. Vibration was only intrusive above 5,000rpm, thanks to the balancer and rubber mounted bars and pegs. Cycle wrote, “The FT is so easy to ride along twisty roads and around town, that’s where the Honda excels.”

Honda replaced the FT500 in 1984 with the V-twin VT500F also called Ascot after the fabled flat-track arena, but this was also dropped the next year. If buying an Ascot, watch for head gasket leaks and starter sprag clutch issues.

• Engine: 498cc air-cooled OHC 4-stroke single, 89mm x 80mm bore/stroke, 5-speed
• Power: 34hp @ 6,200rpm (claimed)
• Top speed: 94mph (period test)
• Weight (wet): 375lb (171kg)
• MPG: 45-55 (avg.)
• Price then/now: $2,198 (1982)/$2,500-$4,500

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