Hop onto the seat and the YZ doesn’t feel as teeny as other bikes in its class. This makes the cockpit more accommodating for riders of above average height. The ergonomics aren’t too tight plus the bike’s fit can be tailored by adjusting the position of the Pro Taper handlebar. To do this Yamaha machined four holes into the top clamp. We utilized the forward mounts with the bar clamps reversed which places the bar in the second-most forward position.
This allowed us to scoot forward on the seat thereby placing more weight on the front of the bike for even better turning.
Other nice touches are the shape of the seat with gripper material on the sides and the humongous foot pegs which help provide a nice platform to work from as well as distribute energy load when landing off obstacles. Lastly we also appreciated the curvature of the radiator shrouds that not only look cool but are shaped in such a way that it’s almost impossible to hook your leg or boot on it.
Although the Yamaha still employs a conventional carburetor it works well even compared to the current crop of fuel-injected 250Fs. A choke knob needs to be pulled when the engine is first fired in the morning. Then it can be started within one or two prods of the kickstart lever. Once warm, the engine can be re-lit without the choke, however the handlebar mounted hot start lever needs to be depressed to aid in hot starts.
Carburetion proved to be spot-on and the engine responded instantly when the throttle was twisted. The only time we ever experienced any hesitation is if you ride in too high of a gear and slam open the throttle at very low rpm. Otherwise it ran well.
Out on the track the engine delivers healthy acceleration right off the bottom. It feels strong but at the same time it isn’t so powerful that it overwhelms the rider or the rear Bridgestone tire. The engine spools up quickly, but as rpm increases the powerband remains flat without a hint of hit or power rush typical of 250F-class motorcycles regardless of rpm.
“The engine has great bottom to mid-power. It pulls well right out of the corner but once you get going it feels flat up top,” commented our test rider Chris See. “Its powerband feels like the exact opposite to other 250Fs. But I think it will be good for someone who is just starting to ride or maybe a vet guy. Even though it isn’t fuel-injected it actually runs really well and didn’t bog for me.”
Considering how linear the powerband is it can be easy to dismiss the YZ’s engine as being slow. But it’s not. It’s just builds power so smoothly that it’s deceptive. In a way the engine feels like an electric motor with its immediate power delivery. However rather than twisting the throttle harder to accelerate you instead need to upshift and work the transmission to gain speed.
Speaking of the gearbox, it works without flaw offering a positive feel during engagement even when loaded while motoring up Glen Helen’s notoriously steep hills. Equally as pleasing is how light and responsive clutch action is, though our pro test rider said it faded slightly at full-on race pace. To compensate the rider has to adjust it with the plastic quick adjust knob while riding.
Without question the highlight of the new YZ250F is its chassis. Compared to other 250Fs where you can get away with being a bit further back in the seat while turning, the Yamaha responds best when the rider scoots his body all the way to the fuel filler cap. When done so it changes direction with high level of precision. However, if you sit farther back in the seat the bike resists quick direction changes and plows through turns so correct body positioning is important.
Once initiated the bike steers predictably never turning more or less than what the rider inputs through the handlebar. The rear end of the bike feels in sync with the front, squatting nicely and resisting the urge to compress aggressively, buck, or slide out even at an elevated pace. Even at higher speeds the chassis continues to serve up a level of stability that other bikes wish they could match.
Suspension-wise the Yamaha employs a two-way adjustable Kayaba Speed-Sensitive fork and four-way adjustable Kayaba shock absorber. A common complaint for heavier and/or faster riders is how soft stock 250F suspension is, but the YZ250F’s set-up actually performed well even for the speed of our test rider. The suspension settings front to back are well balanced and the bike doesn’t pitch or squat excessively despite being undersprung for our 170 lbs pro-level test rider.
“Handling was great,” says See. “The rear end was good; nice and planted. For me I’d probably need heavier spring rate in the fork and shock, but the valving still felt good—I probably wouldn’t need to change it. The suspension is supple initially then has a fair amount of damping as you get deeper into the stroke.”
The OE-fitted Bridgestone tires offered a fair amount of traction in the sand and loam at Glen Helen and even in the afternoon hard pack at Piru. While the Yamaha’s brakes serve up a high amount of feel they don’t have a whole lot of power which occasionally caught us by surprise when bombing down some of Glen Helen’s downhills. Braking power was consistent though even under hard and repeated use.
Overall we really enjoy riding the new YZ250F. While we weren’t exactly wowed by the outright power of its engine—it is very useable making the bike easier to ride for longer. What we did like is its well-sorted chassis and pleasing ergonomics which help make it an effective motocross bike on the track. It’s also important to note that the Yamaha is the only bike to come with a 30-day warranty against manufacturer defects, not to mention the $3 million of contingency up for grabs at 90 racing events in 2011. Yamaha is also the only manufacturer to offer its 250F in two colorways: Yamaha Blue/White for $7150 or for an extra $100 you can get it in White/Red with black wheels and a gold chain.
Specs:
Engine: 250cc liquid-cooled Single DOHC; 5-valve
Bore x Stroke: 77.0 x 53.6mm
Compression Ratio: 13.5:1
Fuel Delivery: Keihin FCR MX37 carburetor
Clutch: Wet multiplate; cable actuation
Transmission: 5-speed
Final Drive: Chain; 13F/49R
Fork: Kayaba Speed-Sensitive System 47mm fork; 20-position compression and 20-position rebound damping adjustment; 11.8 in. travel
Shock: Kayaba gas charged shock, 20-position low-speed and step-less high-speed compression damping, 20-position rebound damping and adjustable spring preload; 12.0 in. travel
Front Brake: 250mm wave disc, dual-piston caliper
Rear Brake: 245mm wave disc, 1-piston caliper
Front Tire: 80/100-21 Bridgestone M403
Rear Tire: 110/90-19 Bridgestone M404
Curb Weight: 225 lbs.
Seat Height: 38.9 in
Wheelbase: 57.7 in
Ground Clearance: 14.8 in
Fuel Capacity: 1.7 gal
Colors: Team Yamaha Blue/White; White/Red
MSRP: $7150 - $7250
Warranty: 30-day
No comments:
Post a Comment