Cycle News - Archive Issues - 1980's

Cycle News 1987 09 16

Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles

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The VZ125 isn't as radically changed as the 250, but it still features plenty of internal refinements. All the VZs have new handlebars - yea! valve area and a tou ched up YPVS, similar to th at of th e 250's. The clutch on th e 125 has been strengthened by adding one more clutch plate and clutch spring. The springs have an overall lower spring rate for a lighter clutch pull. The only change in th e six-speed transmission is a 2mm larger diameter input shaft. The ignition has a larger rotor but the weight remains the same to maintain the same flywheel effect. Plus, th e ign ition curve is altered to rai se th e rev ceiling. Other than th e n ew cartridgedesigned fork , th e YZ's su spe nsion is basically unchanged excep t for some small valving alterations. The linkages are th e same. The least changed of all th e YZs is th e 490. It retams the air-coo led motor, five-speed transmission and rear suspens io n. The only difference betw een th e 1988 model and last year 's 490 is th e Iront fork. It, too, has th e car tridge Kayaba . Changes to the YZSO were made mostly in the motor. Porting in the cylinder has been modified, but th e most no tabl e difference is the use of a fl at-top pi ston to improve combustion efficiency, The cylinder head has a sha llower profile to match the new piston, which also increases compression ratio. The exhaust pipe is also new. Su spension a nd chass is remain th e same excep t for a bracket added to the swingarm to strengthen the chain guide, a nd the pet cock on th e g-as tank has smoother opera tion . Riding im pressions We had a cha nce to spend a da y riding th e preproduction YZ125,250 and 490 for quick impressions, By far , the most improved of the three motorcycles is th e YZ250. Basically, it 's nothing like last year's model it ' s a totall y n ew motorcycle. The motor is extremely torquey and pulls hard through out th e pow erband without th e traditional YZ hard hitting "bwaap" when th e motor comes on the pipe. The powerband is su pe r sm oo th . It doesn 't reac h any eart h -sha tter ing speeds on top end, but ge tting th ere is pure delight. It ch ugs at low rpm for quick getaways in the turns. The Yam ah a sh ifts a lot easi er now , thanks to the new location of th e shiftshaft; the redesigned clutch works smoother, making the motor easy to con trol. -, T he suspension o n th e YZ we rode was by far better than any YZ we've ridden. The cart ridge forks made a huge difference for the better, and the rear suspens io n soa ked up the jolts . without harsh bottoming. The new loca tion of th e swinga rm mak es th e Yamaha mu ch easier to co nt ro l when powering out of th e turns. The front end still has a tendancy to rise, but it's mu ch more cont ro lla ble than The YZ490 is basically the same except for the fork. It's a Kayaba cartridge design. 15

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