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(Left) The "Big Wheel" is a blast to tum in the sand but not on hard-packed dirt. (Below) A jackshaft sat-up must be used on the chain drive. Test: Yamaha's BW200N 1\ IlifJ "Tllf~f~1 .. . if)I-lti!J I,ifls By Kit Palmer A two-wheeled All Terrain Vehicle (ATV) isn't a' new idea. Actually, 12 years ago, Suzuki int,roduced a two-wheeled, balloon tired, rotary-valved-two-stroke-powered RV90. and RVl25 called Rovers. They appeared shortly after the introduction of the Honda ATC90 three-wheeler; both • 24 were new inventions from Japan intended to be ridden on sand dunes, deserts and beaches. However, neither caught on very well, and Suzuki soon dropped the Rovers from its line. The Rover was underpowered, overweight and had scary 'handling habits. The ATC90 created just enough interest to keep Honda manufacturing the three-wheeler, which eventually evol ved into the creation of the 1855 in 1979; and thus, the thrlle-wheel boom. Now we have a new two-wheeled ATV from Yamaha calIed the BW200N. Could the new BW200 start a two-wheel ATV craze like the 1855 did for three-wheelers? The basic design of the BW is all new. but many parts used to build it are from other Yamaha's. For example. the engine isn't new; it is also used in the 200E three·wheeler and in some of Yamaha's current dual-pur- pose bikes. It is a single overhead cam (SOHC), single cylinder, two-valve four-stroke, and the bore and stroke is 67x55.7mm. The actual displacement is 196cc and the compression ratio is 9.5: I. The intake valve size is 34mm, while the exhause valve is 28.5mm. Intake and exhaust valve lift is 0.306 and 0.308 inches. Timing is 26°-60" for the intake and 70°-24° for the exhaust. A 24mm Teikei carburetor draws air from a circular foam air filter well hidden within a plastic airbox. The BW200 has a wet sump, and Yamaha recommends using 20w-40 oil - preferably Yamalube fourstroke oil. Total capacity is 1.4 quarts, and the oil filter is located at the top of the right crankcase cover - unscrew three philIips-head screws and the filter is accessable. Yamaha suggest cleaning or replacing the oil filter every three months. The exhaust pipe exits the cy linder around the left side of the front downtube frame and curves around to the right side of the bike. At the end of the pipe is a U.S. Forrestry Department-approved spark arrester/ silencer that is huge, made out of steel and easily rebuldable. The clutch is a wet-type and is cable operated. The transmission has fi ve speeds, and the shifting pattern is one-down-four-up. The shiftlever is made of steel and sticks way out to the side where it's exposed to rocks and berms. Since the rear tire is so fat. the BW needs a jackshaft arrangement for the chain drive to clear. The jackshaft runs through the left side of the massive steel swingarm ahead of the tire; it carries one sprocket inside the left arm, another outside the left arm. A chain from the engine coutershaft sprocket drives the inside jackshaft sprocket; the outside jackshaft sprocket drives the rear wheel sprocket. A large plastic cover guards the outside sprocket and chain. The countershaft sprocket has 12 teeth and the re,IT sprocket has.46; the jackshaft sprockets have 14 teeth. . To make starting the BW easier, the kickstarter lever is linked by a cable to a compression release on the cylinder - as the starter lever moves, it opens the exhaust valve slightly. A CDI ignition system is used on the BW, and the spark plug is an NGK D8EA. The BW also has a flywheel magneto generator system that powers a 12 volt/45 watt headlight and five watt tailIight. The single-downtube frame is made out of steel and is painted red. The engine is a stressed member of the BW's frame, bolting between a single downtube and the frame's rear section. Wheelbase is 54.3 inches; rake is 27.25 0 and trail 3.5 inches. OveralI length is 78.1 inches, width 32.7 inches. The ground to seat height is low at 31.3 inches. Ground clearance is only 9.4 inches. Suspe)1sion parts are made by Kayaba. The BW has a steel boxsection swingarm with a dual shock arrangement. The shocks only have preload adjustments with five settings. It comes stock on the secondto-softest position. The shocks are mounted far Forward on the swingarm at a slight angle. The lower shock mount is located only nine inches behind the swingarm pivot. and rear wheel travel is 6.3 inches. Up front' is a non-air-adjustable telescopic fork with 33mm stanchion tubes. Red fork boots protect the stanchion tubes from rocks and debris. Travel is the same as the rear at 6.3 inches. Both knobby tires are monsterous: The fron t tire size is 25x8-12 inches, while the rear is 23x 12-9 inches; they are made by Dunlop and are tubeless. The one-piece. four-spoke bolt-up wheels are made of aluminum. Front and rear brakes are 4.3 inch drums. Connecting the rear brake lever to the brake arm is a straight steel rod. Fuel capacity is 1.7 gallon.s. and the plastic tank is white with orange and red-stripes. The BW has a bright red safety seat. Dry weight is 242 pounds. Starting the BW when cold isn't a problem. It usualIy fires up by the third or fourth kick; when warm, it only takes about two kicks. Dropping the transmission into first gear from neutral when at idle doesn't produce a loud clunk. When the clutch is engaged the BW lurches forward; because of an abundance or torque, the big·wheeled Yamaha works best down low in the powerband. It will chug along at low speeds, and a quick blip of the wot·