Yamaha Wr 500

YAMAHA WR 500

CYCLE WORLD TEST

There's a new tractor in town

YAMAHA'S VENERABLE YZ490 WAS OUR LEAST-FAvorite dirtbike. Its engine vibrated strongly enough to mix paint. It pinged like a Corvette with a tankful of Baja gas. It challenged its rider with soft low-end power that transitioned to a mid-range jolt with all the subtlety of a whack from a sledgehammer. And that wasn't ail: The 490's frame flexed, its harsh rear suspension had gone too long without a redesign and the bike turned and handled with the ease and precision of a 10-wheeled dump truck. A fully loaded one.

Yet Yamaha sold thousands of YZ490s between 1982 and '90, mainly to trail riders who didn’t want the apparent complication of more contemporary liquid-cooled off road mounts.

So when it finally came time to change the big YZ Yamaha didn’t want to alienate past buyers, didn’t want tc mess with a formula that worked on the sales floor. Which brings us, finally, to the YZ490’s replacement, a prim« example of how careful engineering can solve problems.

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Yamaha figured this new bike needed the same sort of air-cooled engine that powered the YZ. so the old powerplant was retained. But it was modified to correct some of its trouble spots. In an attempt to reduce pinging, the head’s combustion-chamber shape was changed, the compression ratio was lowered half a point, to 6.7:1, and a new' ignition with less advance was used. A 38mm roundslide Mikuni carburetor replaced the 40mm mixer through which the 490 had drawn breath, and a new pipe and silencer were designed to further smooth and broaden the engine’s powerband.

This improved, yet still traditional-looking engine was wrapped with a new frame, suspension, brakes and bodywork. And then it was renamed. Meet Yamaha’s WR500.

The finished product should bring grins to the faces of YZ490 fans, and to those of the old bike’s critics, too. First, that redesigned engine: Gone is the worst of its vibration, thanks to a head-stay bracket and a larger center engine-mounting bolt. The 500’s powerband is smooth and controllable, with tractor-like low-end power that builds to a potent midrange burst that is followed by a great top-end run. The unchanged, wide-ratio five-speed transmission still has notchy shifting, and the clutch pull remains heavy, but missed shifts are rare and the transmission ratios are well-matched to the engine’s power.

The WR’s frame, aluminum swingarm and shock linkage are much the same as those of the ’91 YZ250, but have been strengthened and modified to take the added punch of the 500 engine. The new frame’s steering-head angle is less steep, its tubes have thicker walls, and the swingarm is longer than that of the YZ and is fitted with snail-type axle adjusters. Additionally, the rear suspension’s linkage arms have lube zerks for ease of maintenance. And, a first for Yamaha, the WR500 has a removable rear subframe.

This attention to the frame has been worth the effort, as where the YZ490’s handling was spooky at best, the 500 is very predictable. It turns with little effort, goes exactly where it’s pointed, flies straight off jumps, doesn’t twist or creak across gnarly surfaces, and is rock-steady at speed, even in sand.

Also praiseworthy is Yamaha’s work on the WR’s suspension. The fork and shock soak up small ripples and bumps nicely, have smooth progression throughout their strokes, and seldom bottom on the big stuff. Both ends are adjustable for compression and rebound damping, too, so even the pickiest rider should be able to adjust the 500 to his satisfaction.

This fine frame and suspension are enhanced by a narrow but comfortable seat, well-placed hand and foot controls and a roomy riding position. A 3.4-gallon fuel tankwith its front edges shaped to mimic the radiator air scoops of liquid-cooled bikes—is narrow at its rear and carries its fuel fairly low on the bike. Moving about on the 500, whether seated or standing, nothing gets in the way, nor does the bike feel too wide.

At least one thing remains unchanged: Just as the 490 was, the 500 is a beast to start. The kickstarter is long enough to provide sufficiënt leverage, but the engine still requires a lot of leg to get it spinning fast enough to light up, especially when it’s cold-figure on 10 to 15 kicks to get the engine running. Like the old 490, you know the WR500’s engine is about ready to run after it backfires on the seventh or eighth kick. When warm, one or two healthy stomps on the lever will do the trick.

Except for the cold-starting chores, the WR500 is so much better than the old 490 that we wish Yamaha hadn’t waited so long to build it. The 500 gobbles up steep hills without breathing hard, slides fireroad corners with great control, smooths all manner of bumps without jarring its pilot, exhibits fine high-speed stability, and provides disc brakes that are strong, progressive and quiet.

It’s an outstanding motorcycle. The changes made to the YZ490 engine have transformed it into a terrific doeverything powerplant, and by wrapping this updated engine with a modern frame, wheels, brakes and plastic components, Yamaha has created a great do-everything offroad bike. We’re impressed. gg

YAMAHA WR500

SPECIFICATIONS

$4299