Our first few dates have been civil; time will tell what course our relationship with the 2005 WR450F will take, but we are looking forward to measuring the big blue bike against the rest of the growing 450 class. The latest from the Yamaha factory has plenty of promise; it has already demonstrated excellent performance capabilities while remaining quiet and with emissions gear included-something we're mighty pleased to see.
WR250F
Perhaps the biggest bummer with the WR250F is that California owners will have to wait until 2006 to see AIS and thus a green sticker on the little WR. Although the system exists and Yamaha was ready to equip the bike with the unit, the paperwork hit a red-tape bottleneck and it could not get the required stamps of approval in time. That said, there's one word to describe this bike: fun. Receiving nearly all of the same updates as its bigger stablemate yet weighing in 16 pounds less, the WR250F feels more compact and is certainly less brutish. You can ride the 250 harder without getting into trouble nearly as quickly as with the bigger WR. A word of warning: Don't ride the smaller 250 in a tight section (or anywhere besides deep sand) and then hop back on the 450; you'll be ruined. As on the WR450F, before we tackled any serious riding the WR250F got its throttle-stop screw replaced with a YZ-F version, the 82-decibel exhaust insert removed and that gray wire under the tank disconnected.
Unique to the 250, and just the opposite of the 450, a taller, flatter piston head was incorporated to keep the 12.5:1 compression ratio for an improved delivery at low rpm. When the surface of the combustion chamber was made all smooth curves rather than angular outcrops, the volume of the combustion chamber actually increased, so a 2004 piston would have resulted in a lower compression ratio. Yet in spite of efforts to boost low-rpm response, the WR250F is still fluffy down there and demands to be ridden like a 125. But don't mistake this as a weak engine. This little bike rips; the engine revisions add up to a major boost of muscle. You just need to keep the throttle open-a lot. Unlike the 450, the 250 takes a little while to build up steam if you let it drop off the pace. This soft bottom is nothing new to seasoned WR250F riders. In our experience, a free-flowing but still quiet silencer usually helps cure it.
With its major downfall of girth removed, the Yamaha is a serious threat to its main rival, the CRF250X. Although the Honda has more torque and a cleaner response off idle and at low rpm, the WR-F feels as though it has more gusto throughout the rest of the powerband. It accelerates hard, cleanly and for a long time, yet it doesn't tire out the rider or require effort to change direction. The suspension didn't present the same mysteries as the 450's, either. Four clicks out on the fork compression, set the sag at 100mm and it was smooth sailing. Did we mention this is a quiet bike? Under 96 decibels and still raging-we like that. For trails that require weaving between tight trees or even just exploring a single-track, this is probably the better tool from the Yamaha store. For sure, this will be the bike that has the staff bickering like two kids forced to share the same toy.
What's Hot!
* WR450F is green sticker-legal and still hauls butt!
* New light and trick-looking aluminum silencer that keeps the bark under 96 decibels (after removing the quiet insert) without a choked-up engine.
* Slim body and low cg that translate into markedly improved agility.
* Super-smooth power delivery and more of it.
* Renthal handlebar stock.
* The seat and tank can be removed using only one 10mm T-handle.
* Phillips-head shroud screws replaced by 8mm hex-head bolts.
* Race ready after you mount your favorite hand guards.
What's Not!
* Fans of couchlike comfort will be disappointed in the wafer-thin seat.
* Range is short, thanks to a minimalist 2.1-gallon fuel tank.