The big Yamaha single
Years made: 1976-1981
Claimed power: 27hp @ 5,500rpm
Top speed: 90mph
Engine type: 499.4cc SOHC, air-cooled single
Weight (128kg): 282lb
Price then: $1,398
Price now: $500-$2,000
MPG: 35mpg (approx., offroad)
Gordon Mizuhara was an unusual teenager: He was never, ever interested in motorcycles. But he did want his own wheels, and carefully saved his money to get a set, at some point realizing he had enough for either, (a), an old beater of a car or, (b), a cherry 360T Honda motorcycle. He bought the Honda.
Naturally enough, after owning the little Honda for a few weeks, Gordon was suddenly an enthusiast. Then he started noticing the hotshots in his ocean-side neighborhood in San Francisco, many of them riding Yamaha 500 singles. “People would race them up and down the Great Highway. The Yamaha TT500 has stump-pulling torque, and some people could wheelie a TT500 for blocks. It was the Wheelie King,” Gordon says, and that got him hooked on the big Yamaha single.
Although the Yamaha TT500 was last imported into the U.S. in 1981, the lightweight, fun single still has tons of fans. “I don’t remember when I got the first one, but I’ve definitely been bit by the Yamaha 500 bug,” Gordon adds. “I have been collecting all three varieties — the TT offroader, the XT enduro bike and the SR road machine. I own eight now, and this bike is the earliest one in my collection.”
Rise of the machine: The 4-stroke motorcycle
Although Yamaha got its start in the 1800s building instruments, it turned to motorcycles after World War II, when producing inexpensive transportation was one of the sure bets in the uncertain world of occupied Japan. Exports fueled the company’s growth — particularly to the U.S., where the company established an export arm in 1961 — and by the late 1960s Yamaha’s American market was probably bigger than its Japanese market, and possibly Yamaha’s single biggest source of income.
A lot of that success came from paying attention to the market. The Yamaha DT-1 scrambler introduced in 1968 was specifically built for the U.S. market, and was a huge success. “It was reliable,” explains John Reinhard, a former Yamaha USA employee and now owner of Ken Maely’s Hot Shoes (famous for its custom dirt track racing boots). “The levers would stay on the bars. Everything would work,” he says in obvious reference to the less-than-reliable fare coming out of the U.K.
Yamaha built its first 4-stroke motorcycle, the 650cc XS1, in 1969. The XS, with heavy input from Yamaha’s marketing researchers in the U.S., was designed to look like a British twin and was a hit in the U.S. Yamaha came out with other road-going 4-stroke motorcycles (think TX750 and 500), but compared to the 650 they flopped, mostly because of reliability issues.
Yamaha’s road-going woes were contrasted by its offroad successes. Yamaha 2-stroke scramblers and offroad bikes like the DT sold well, but as the 1970s dawned, the company knew that a new era of environmental legislation would make 2-strokes a difficult proposition.
Meanwhile, Yamaha USA’s sales department had uncovered a niche market for a 500cc 4-stroke thumper, like those previously made in England. BSA Gold Stars and single-cylinder Matchlesses had excellent torque and made usable power in a wide variety of offroad conditions, and by 1971, both BSA and Matchless were out of business. Further, while American enthusiasts appreciated the power and handling of the big British singles, they could get along without their weight and maintenance. Yamaha knew that any proposed 500cc single would have to be both reliable and light in weight.
Yamaha USA’s first step was to locate and purchase an Eso motocrosser. Eso had been founded in Czechoslovakia in 1948 to build speedway racers, but it also built a few motocrossers in the mid-1960s. These 4-stroke singles incorporated many modern ideas and were much lighter than the British thumpers. One was found in California and was shipped to Japan for study purposes about 1971.
Two or three years later, Yamaha sent a prototype to its American exporter, who turned it down as inadequate. But in the summer of 1975, the same engineers came out with a winner, although making the 4-stroke thumper work properly was, according to project leader Shiro Nakamura, a nightmare. Yamaha kept the short-stroke concept of the prototype, but made it produce horsepower.
The first Yamaha TT500 appeared at Yamaha's September 1975 dealer’s convention, and it was an instant success in the showroom and in competition, especially in long, grueling African races like the Paris-Abidjan-Nice. The new TT500 was reliable, had a wide power band and produced loads of torque, just like a thumper should. Power delivery was good for offroad work — and in a welcome change from the old days, it was easy to start.
With the TT500’s success, Yamaha saw an excellent foundation for more models. For 1976, Yamaha offered the XT, a more road-going version with minimal lighting. This was followed by the Yamaha SR500, a full-bore road bike, in 1978 (see Motorcycle Classics, March/April 2006). The SR500 quickly became a cult item, with Japanese and American aftermarket manufacturers producing go-faster parts and cosmetic disguises intended to turn the Yamaha into a Velocette or BSA Gold Star clone.
While the Yamaha TT500 never made much of a mark as a motocrosser, it proved itself in long distance offroad racing. TT500s won the first two places in the inaugural Paris-Dakar rally in 1979, and the first four places in the rally’s second running. The TT500 was produced for six years and was then discontinued in favor of the XT version, which was built up until 1990. The SR500 is still built in a 400cc version for the Japanese home market.
Enter Gordon Mizuhara
Motorcycles have become something of a passion for Gordon, who tells us he’s had some 100-odd bikes in the intervening years since that first Honda 360, including the eight TT, XT and SR500s he owns now. And he’s presently restoring a real 500 rarity: a Dick Mann Specialties Yamaha TT500 with frame, swingarm and exhaust designed by the two-time national champion.
Gordon found our feature bike, a 1976 Yamaha TT500 through a newspaper ad. The prior owner claimed it was the second TT500 sold in California, and while there’s no way to confirm the claim, it is a first year, low serial number — no. 42 — TT500. It was all correct except for the exhaust, which had been swapped for a more powerful aftermarket item. Gordon bought the bike, rode it around a little, and put it in his collection. Several weeks ago, he was idly trolling through Craigslist, and came across a beautiful, very lightly used stock exhaust. “This is a very rare item — it was one year only,” Gordon says. The pics here are the bike’s first outing with the correct exhaust.
An aircraft mechanic by trade, Gordon’s interest in the Yamaha TT500 is fueled by its excellent engine design. “The engine design is bulletproof. With the camshaft, crankshaft and connecting rod big end resting in roller or ball bearings, this was an engine designed to last, and it does,” he says. “This is still a very popular engine to modify, as the engine was over designed — it can easily handle the added power from hop-up items,” he says. “Popular mods are a White Brothers or SuperTrapp exhaust, K&N air filter, a higher compression and/or bigger piston, a bigger carburetor, a higher lift cam and stiffer valve springs. You can modify it heavily, and it will still perform.”
That said, Gordon’s not immune to some of the bike’s weak points. “There were some problems with this bike, especially the 1976 model,” he says. “It didn’t have the piston indicator gauge to show when the piston had passed top dead center, which reduced the chances of the engine kicking back and slamming the rider’s knee into the handlebar. Experienced riders always turn the bars to the left so if the engine kicks back, the rider’s knee won’t hit.” Gordon also notes that the stock exhaust on the first year TT wrapped around the right rear shock, causing the shock to overheat and eventually fail. Yamaha fixed the problem by redesigning the exhaust for the 1977 model.
Those niggling issues aside, the TT was built for the long haul and holds up well to use. Easy to own, maintenance on the 500 is about the same for any dirt machine, allowing for age. “I like to use semi-synthetic on my TTs. Full synthetic is too thin for older air-cooled engines. I change the oil and adjust the valves about every 3,000 miles. You don’t have to tinker with the one carburetor — once it is dialed in, it stays there,” Gordon says.
“The TT500 has lots of power and lots of torque. One thing that attracts me is that the bike is a good ergonomic fit for me,” Gordon continues. “I am 5-foot-8, and the low seat height and foot pegs, and handlebar placement, fits me to a T. The brakes are adequate — the Yamaha stops, but you can’t compare it to a modern-day bike.” MC