Articles specific to Yamaha.
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The YZ250F changed the motorcycle landscape with its introduction in 2001. It was almost silly to think that 250cc four-strokes were allowed to race in the 125cc class with the smaller two-strokes as of just a few years ago. At the time, there was no such thing as a small-bore four-stroke race bike. After Yamaha won 5 of 8 races in the 125cc Western Regional Supercross Series in the YZ250F’s debut year, and claimed that championship, many other manufacturers scrambled to introduce their own 250cc four-strokes - but those bikes still don’t hold a candle to the original. The bad news for them is that the 2005 YZ250F features many updates over last year’s multiple magazine shootout winner.
The YZ four-stroke receives a redesigned cylinder-head combustion chamber with a smoother intake port and a further-convexed piston head for improved performance and traction. A funnel-type air box is adopted for 2005, which increases the ease of airflow and improves the power output. The YZ250F won shootouts last year based on its power output alone, so stepping up the power is a big deal. This very capable powerplant is mated to a standard five-speed, close-ratio transmission, which will allow you to rev it out in any gear, or short-shift it and keep it in the meaty lower-end of the powerband. This bike hauls the mail.
And as for handling, the YZ250F comes with the all-new Air/Oil Separate System front fork with what’s called TCV (transfer control valve) for stable damping, improved mid- to full-stroke performance and better rider feedback. Basically, riders will have less fatigue and more feel for the bike. To complement the new fork, the rear suspension has been upgraded as well, as the swingarm itself is now redesigned to be lighter and stronger, and the new rear shock features a full-rebound oil-lock circuit for a smoother ride in the rougher parts of the track. Put them together and it adds up to outstanding handling in the turns, in the rough, and upon landing.
To ensure the continuing dominance of the YZ250F, it will come straight from the factory with aluminum handlebars made by Renthal – long considered the aftermarket standard. In the past, standard steel handlebars were frequently the first things replaced after purchase, but now that’s not necessary. Not only does that save a further 90 grams of weight, but it also saves the buyer about $100 at the dealership. To go with the new handlebar, the YZ250F will feature a shorter, re-routed front-brake hose for improved brake feel and easier bleeding.
The disc brakes on both ends feature lightweight calipers and aluminum pistons mated to a 250mm disc (front) and 245mm disc (rear) providing excellent stopping power, and the 21-inch front and 19-inch rear rims provide outstanding durability and reduce un-sprung weight, which allows for optimal suspension performance and handling. Mounted to those high-end Excel rims are premium Dunlop 739 race tires. The YZ250F still features a trick works-style clutch lever with race-spec barrel adjuster for on-the-fly adjustments, as well as a handlebar-mounted hot-start lever for ease of starting after a fall or stall. And for weight savings, it comes with super-trick, lightweight titanium foot-pegs, just as the rest of its YZ siblings do.
The YZ250F is now faster and handles better. What is more important than power and handling? Nothing. That’s our point. The YZ250F was the first in its class, and it’s still in a class of its own. Suggested Retail: $5,699 USD.
Engine Type: 249cc, liquid-cooled, 5-valve, DOHC, 4-stroke w/titanium valves, Digital CDI
Bore x Stroke: 77 x 53.6mm, Compression Ratio: 12.5:1
Carburetion: 37mm Keihin FCR flat-slide w/throttle position sensor
Transmission: 5-speed w/multi-plate wet clutch, Final Drive: #520 chain
Suspension, Front: 48mm Kayaba inverted cartridge fork w/adj. comp. & rebound; 11.8" travel
Suspension, Rear: Kayaba shock w/adj. preload, comp. & rebound, separate hi/lo comp. adj.; 12.4" travel
Brakes, Front: 250mm floating disc, Rear: 245mm disc
Tires, Front: 80/100-21 Dunlop, Rear: 100/90-19 Dunlop
Dims: L 85.2", W 32.6", H 51.3", Wheelbase 58", Seat Height: 39.2", Ground Clearance: 15"
Dry Weight: 206 lbs.
Fuel Capacity: 1.8 gallons
Color: Team Yamaha Blue/White
- Redesigned combustion chamber, piston, intake ports, carburetor jetting and airbox for improved combustion efficiency and power.
- Redesigned CDI unit for optimal ignition timing.
- All-new fork with TCV (transfer control valve) for stable damping, improved mid- to full-stroke performance and better rider feedback.
- New, aluminum Renthal handlebar is 90 grams lighter and more durable.
- Revised triple clamps for even better handling.
- Shorter, re-routed front brake hose for increased brake feel and easier bleeding.
- Lighter, stronger swingarm with stronger new linkage for better performance and durability.
- Rear shock has a new, full-rebound oil lock circuit for a smoother ride.
- New-design rear sprocket and chain guide reduces wear, chain wobble, and noise for more efficient power transfer.
- Rear brake bracket is 35 grams lighter, and designed for easier rear wheel installation.
- New front fork protectors are larger for better coverage.
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