First Impression: 2004 Yamaha YZ125

Yamaha invited TransWorld Motocross out to Perris Raceway today to take delivery and take our first ride on the new 2004 YZ125. Yep, it’s that time of year again, and it’s hard to believe that the new bikes are already starting to arrive. With so much attention being paid to the slew of new 250cc four-strokes set to land on dealership floors later this summer, Yamaha set out to continue their refinements, and their dominance in the world of 125cc two-strokes.


There’s no doubt that the explosive power of the four-stroke has raised the bar for all 125cc class machines, and Yamaha has certainly stepped up to the challenge by producing yet another potent 125cc package. The 125 class is a hotbed for research and development, and with the highly successful YZ250F and a two-stroke 125 that continues to impress, Yamaha has clearly been doing their homework!

With a 2003 package that won multiple 125 shootouts, including ours, Yamaha made only minor refinements to their 2004 YZ125. Make no mistake about it though; the refinements are right on, producing another YZ125 that rips! The most highly anticipated change to the ’04 is the addition of a newly designed 48mm front fork for even sharper handling. The new, larger diameter fork also features a special treatment to help reduce friction, and a new hydraulic bottoming system, producing an even plusher ride. Although we rode the new YZ on a fairly smooth Perris Raceway, we could feel the definite improvements to an already great front end.


Additional chassis features include an all-new upper triple clamps; a new “Gripper” style seat cover; wide, cleated titanium footpegs; and lightweight front and rear calipers with aluminum pistons. With various steel hardware getting swapped out for aluminum, along with the other aforementioned refinements, the new YZ weighs in at a full pound lighter than last year’s model.


In the motor department, the YZ125 cylinder features updated port timing giving a harder-hitting midrange and even more power up top. Yamaha’s patented YPVS (power valve) system received updates along with a revised carburetor bypass port, all-adding up to crisper, smoother throttle response. Add to the mix an all-new ignition and a 5mm longer header section, and you get yet another new model YZ125 with a ton of smooth, useable power.

Our resident pro tester Michael Young was impressed with the changes made to both the front fork and the motor. Coming off of a serious knee injury, Michael wasn’t able to pound out an entire moto to put the YZ through its true paces, but he felt right at home on the new model, and can’t wait to ride it again during our 125cc shootout. You can see him in action by clicking the supplemental link to the video in the right-hand column.


As a package, the YZ will one again be a tough bike to beat. Stay tuned for a full-length bike test of the 2004 YZ125 in the October issue of TransWorld Motocross, as well as the 2004 125cc shootout, also in a later issue.