Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/127691
, . " JEST.'. 1995 Yamaha YZ250 By Kit Palmer Photosby Donn Maeda E ~ 0\ ~ N l-< OJ "S 6 OJ z 6 d Schiedler, from Yamaha's testing department, had that look in his eyes, and that grin. "You 're really going to like this one," he said while handing over to me Yamaha's latest YZ250 MXer. But I've seen that look on his face an d have heard those exact same w o rd s before . Yeah, yeah, I thought. He says that every YCilr. "No. I really mean it this time," he stres sed. "We've m ade some pretty e-jfective changes. I think you 'll like it. Just go out, put in a few good laps, loosen up the sus pension and com e back in and I'll set the ride height." Even though my first few laps on the Yamaha w ere basically to just break in the sus pension, I couldn't help but notice the YZ' s motor. Smooth, very sm oo th . The suspension wasn't bad , either - a little harsh, perha ps, but the m otor! It really caught my attention. Then again, last year's yz wasn't an ything to sneeze at either, it was downrigh t fas t an d pow erf u l. Even the fo lk s at Honda paid it th e u ltimate com pli ment by admitted ly trying to em ulate th e '94 YZ's po werplan t with their new motor in th e '95 CR250. They too noticed h ow many holeshots Yamaha got this year. Despite already having a wond erful motor, Yamaha somehow managed to make it even better, and this became evident after just a few laps on the bike. There is slightly more power on tap, and the delivery, believe it or not, is actually smoother than before. It's almost as if Yamaha took the best qualities from both last year's CR an d YZ motors an d combined them into one awesome package. The '95 yz motor has an electri c kin d of power delivery - similar to the '94 CR250 motor - powerful yet very controllable. "That's because of a combination of thi ngs," sai d Schiedler. "Basically w e wanted to retain the tractability of the '94 YZ but to improve throttle response and pulling power as well." They nailed the bull's-eye, " We added an exhaust resonator to give it a little better performance off the bottom, too" sa id Schiedler. "Then w e changed the contour of th e reed va lve itself and added a d ivider to the center of the reed cage. This was done to improve motor response. "We also went back to the li g h ter crank but reduced the crankcase capacity by 31cc." Yamaha also replaced the Mikuni carb w ith a Ke ih in mixer, which Ya maha cla ims improves low- to m id spe ed resp onse, due to more effici ent air flow aroun d the carb's slide. has a new airbox-toThe new yz also " carburetor boot. "The '94 boo t ha d mo re of a ten d ency to go around the shock spring; now , we mo ved the boo t out on the airbox, giving it (air) a straighter shot to th e ca rb, " sa id Sch ied ler. " We also expan ded the passageway." A t the other end, the intake manifold wa s also res haped. "And then we changed the governor in the power-valve," said Schiedl er. "We cha nged the point where the pow er hits by 1000 rpm. It hits much later, now. The valve used to open at 5800 rpm, now it opens at 6800 rpm. " In our opinion, Yamaha made all the (Above) A super-smooth yet powerful motor make the new Yamaha VZ250 even easier to ride than before. (Below) Whatever rough edges the VZ250 might have had last year have been rounded off for '95, via many small but effective changes.