YAMAHA 2-STROKES

"Before we had any clue about the myriad dangers of triple cheeseburgers, saturated fat, unburned hydrocarbons and street-going two-strokes, there was the RD350. Dirty, foul-mouthed, deliciously quick and relatively affordable, it was a Giant Killer.

Anybody old enough to read a bike magazine back in '75 knew it was true.

From the first '73 RD350 to the last 1975 RD350B, Yamaha's overachieving pocket rocket humiliated triples and fours packing over twice its 347ccs on racetracks and backroads all over the planet. Back when bell-bottoms were cool and Harley's weren't, most anybody's big-bore multi roasted the RD in a straight line. Horsepower was cheap, and any fool could twist a throttle.

But motorcycle handling was still an oxymoron in Japan...except at Yamaha. When seventh-morning services convened at the shrine of the divine apex, street or track, all bowed to the RD. For the proletarian canyon commando, laying down $3000-plus for one of 50 1974 750SS Ducatis was like Led Zeppelin playing the next freshman/sophomore mixer: very bitchin', and highly unlikely. Kawasaki's very fast, very large Z-1 wore a $1995 price tag. But a 1974 RD350 sold for $908: Moet Chandon on a Schlitz budget. Racetrack handling for the masses.

The RD350's street roots stretch back to February 1967, and the YR1--Yamaha's first street-legal 350. But the 1970 R5 350 drew a straight line from brand Y's TR production racers to the street.

Fast forward from the YR1 to the mercifully cleaner lines of the 1970 R5 350. Adding new seven-port, reed-valve cylinders and a few other refinements turned the '72 R5C into the 1973 RD350. Now we're on to something. Even in '73, RD styling was still parked somewhere between tawdry and garish. But 0.010-inch thick spring steel reed valves between 28mm carburetors and the new, seven-port cylinders made all the difference. The 347cc RD twin used classical 64x54 bore and stroke numbers to spin out about 35 horses at 7500 rpm.

Pushing 352 pounds fully fueled, Motorcyclist's admittedly rough-running 1973 test bike covered the quarter-mile in 14.48 seconds at 89.8 mph. Cycle magazine's RD ran closer to its potential with a 14.12-second/93.2-mph blast. Those numbers were underwhelming alongside beasts like Kawasaki's 12-second triples and fours. You could fluster 'Vettes and Hemi 'Cudas roosting away from a light, but the RD wasn't a dragster.

Agile, light, simple and reliable (see "Yamaha RD350/RD400: Charting the Changes" sidebar, p. 64), the RD would take you from work and back Monday through Friday with Clark Kent gentility, offering only the odd oil-fouled B8HS spark plug in protest. It was smooth and comfy enough for freeway travel, allowing gas station pit stops at 100-mile intervals; the thirsty little twin's 3.2-gallon fuel tank called up reserve every 70 miles. Two quarts of oil flowed through the Autolube system every 500 miles or so. But turn up the volume and fuel mileage fit the bike's Bad Boy image. Figure about 26 miles to the gallon if you were loose with the loud handle.

From its birth until Yamaha's FZR400 took over in 1988, the 350 Yamaha two-strokes were pretty much the dominant tool for 400-class production racing on the cheap. San Francisco Bay area RD aficionado Dale Alexander remembers the 350 as a potent, reliable tool once it was set up correctly. "I could race my RD all season for the price of a new FZR400," he says. Before moving on to TZ Yamahas, Formula 1 Suzukis and such, Thousand Oaks, California's Thad Wolff routinely clobbered all comers in the 1979 AFM 400 production title aboard a very rapid RD375 (extra displacement courtesy of TZ750 pistons in chromed bores, spinning a TZ250 crankshaft). "The only competition for a well-set-up RD was another RD," Wolff remembers.

Even without all the good stuff, nothing got through a tight set of corners any quicker than a savvy RD pilot. Motorcyclist's November 1974 test of the RD350B said, "...in everything but all-out acceleration, the Yamaha 350 will probably outperform just about anything on the market in box-stock trim." We griped about hard grips, a little too much engine vibration and footpeg mounts that eroded rapidly at maximum lean. Otherwise, the RD was a gem.

Even a pristine example of the breed (like the 1975 RD350C pictured) will underwhelm derrieres calibrated to current four-stroke sporting weaponry. Still, novelties like really light weight and the two-stroke's rush of dirty little explosions every time a piston heads earthward ("Dang the ozone layer, Scotty, give me acceleration!"). Eco issues aside, it's a deceptively quick little beast to ride.

The RD looks tiny by 1996 standards because it is. Even so, nice flat bars and a seat to match keep six-footers comfy for 100 miles or so between fuel stops. Twenty-year-old suspension bits feel...well, about 20 years old. The little 350 still corners on rails, even if it does wallow and grind its low-slung undercarriage at relatively mild lean angles. But keep rowing the cliche-smooth transmission's six tightly bunched ratios to keep the hydrocarbons burning between 6000 and 8000 rpm and the RD flat out roosts--60 mph arrives in less than four seconds. Even through the tastefully muted stock mufflers, the weed-whacker-on-benzedrine exhaust note is pure heaven.

The RD was the official bike of working-class curvy road cognoscenti in the mid-'70s. As Yamaha product planner Ed Burke says, "The RD was a cult bike if there ever was one." All it took to initiate membership was that velvet shriek rising into your Bell Star. Once you knew what it could do to a perfect road on a perfect morning, nothing else was even close. But all good things must come to an end. Neither the cleaner, more "civilized" 1980 RD400F or the liquid-cooled RZ350 (a story for another day) of 1984 could win the war against progressively faster, more sophisticated heathen four-strokes. Riders demanded bigger, faster bikes. The EPA wanted cleaner ones. The handwriting was on the wall. The RD350 begat the RD400 in 1976, and by the end of 1980 the 400 disappeared from Yamaha showrooms as well.

Modern prototype RD350

Yamaha RC5/350