The YZ125 motor is light and fast, but not as desirable as the 4-stroke.
The YZ125, on the other hand, was far more demanding of its rider. Major clutch work is needed to get a strong launch off the corners, but then it's a struggle to find traction. And when running through the many 180-degree corners, a YZ125 rider has to wait until most of the turning has been completed before popping the clutch to finish it off with a berm shot.
"The 125 seemed slippery," noted MCUSA's Ken Hutchison after a stint on the 2-stroke. "If you're not on the power, it doesn't hold lines well - it seems to skim across the ground feeling like its ready to wash out. But once you put your
foot down and straighten things out, which is simple since it's a little 125, it works well. Once I got used to riding with the power and not being afraid of the screaming wail of the 2-stroke, it started making sense."
Corners are less technical on the 250F, as the tractable powerband allows its pilot to get on the gas earlier. And when it comes time to hook up on corner exits, the 4-stroke's smooth power delivery gets the edge when hunting for traction on Dunlop's excellent 739s.
"The lack of power on the bottom-end of the 125 is painfully obvious," continued Hutchison. "It sure is easy to ride that 250 though, just motor around and do whatever you want."
The YZ125, although acknowledged as one of the best 125s, sat longer in the pits than the 250F ever did.
Once on the pro track, the gnarlier configuration tested the suspension capabilities of the YZs. Both bikes use Kayaba components on both ends: A 46mm fork with 11.8 inches of travel and compression and rebound damping adjusters up front; a single shock with 12.4 inches of travel at the rear, featuring separate high- and low-speed compression damping adjustments.
As you might expect, with the same suspension components, there's not much in it between the two bikes in the way they handle the bumps. Both were able to suck up the smaller hits from whooped-out rhythm sections while still being able to land from big triples.
"The suspensions seem choice and compliant," said Hutchison while wiping mud from his face. "I only bottomed out on the bigger jumps that I over-jumped and landed on flat ground. When landing properly, it was great.
Like the YZ's suspenders, the pair also share the same braking components. Built by Nissin, the 250mm front disc and 245mm rear provide meaty power while remaining easy to modulate. With sufficient traction, it is easy to loft the rear wheel in the air under hard deceleration. But at the same time, there is an abundance of feedback that allows a rider to brake right up to the point of lockup without going beyond.
It is remarkable how compact Yamaha was able to make its 4-stroke engine.
Next stop on our MX tour was Competition Park in San Jacinto, California. Its complement of four diverse tracks gave the YZs a chance to shine in different environments.
With a hearty helping of double jumps and tabletops, there's plenty of air time at Comp Park. And when riding with the wheels off the ground, a discerning pilot will notice that the 250F is harder to toss around. Yamaha claims the 4-stroke YZ has a dry weight of 208 lbs., 12 more than the YZ125. That extra mass, while not exactly a hindrance, can be felt from the saddle.
Another difference between the two is the way they steer. The YZ125 has 56.9 inches between its axles, considerably shorter than the 250F's 58.1-inch wheelbase. This makes getting the 125 turned when blazing into a medium-speed corner a little bit easier. Also, the 4-stroke's greater inertia from its larger engine contributes to it being slightly slower turning.
For 2002, the YZ125 lost a cog in its tranny, joining the 250F in the 5-speed club. Yamaha believes the weight loss is worth the benefits an extra gear brings, and it wasn't really missed during our time with the bike. No matter how many ratios in the gearbox, the 125 is simply outgunned in most situations.
The power delivery of the 250F makes it easier to hook up on loose dirt like this.
"The 250 just works, it makes plenty of torque on the bottom," said guest tester Dave Raffl. "It's a lot more forgiving than the 125 in that regard. You can be in the wrong gear and just stab the clutch and jam. But the 125, it won't pull."
At no time was this more evident than on a particular right-hand corner at one of the tracks at Comp Park. The rutted up turn leads directly up the face of a tabletop jump, and if you don't get a strong drive at the corner exit up the face, you're sure to land on the flat tabletop section instead of the fast way of landing smoothly on the downslope.
This was especially challenging on the 2-stroke because the hit of power delivered from fanning the clutch is abrupt, making it difficult to find traction. Without the clutch work, there's not enough time or space for the peaky 2-stroke to get "on the pipe." So the best technique in this situation is to drift across the stutter ruts with an early apex, and then using the clutch to hammer it off the berm and up the jump.
