Check out the 2015 Yamaha YZ Motocross Line.
Yamaha released information on its 2015 YZ line of motocrossers today, announcing key changes not only to its YZ250f and YZ450F four-strokes but also improvements to its diehard line of two-strokes, which consists of the YZ250, YZ125 and YZ85.
2015 Yamaha YZ450F
Yamaha’s flagship YZ450F underwent a complete revamp for the 2014 model year, so the 2015 YZ450F receives detailing updates rather than a major engineering overhaul. Starting up front, the 450F’s KYB Speed-Sensitive System inverted fork has been changed via stiffer fork springs, new valving and new fork outer tubes in an attempt to improve mid-to-end stroke performance and to make the fork more resistant to bottoming.
Yamaha also worked to make airbox servicing easier on the YZ450f by incorporating quick-release, quarter-turn Dzus airbox fasteners for tool-less access to the air filter.
Yamaha still follows its own revolutionary path via the YZ450F’s engine anand chassis layout, which features a 449.7cc, liquid-cooled, DOHC, fuel-injected four-stroke single with a rearward-slanted-cylinder design that Yamaha claims achieve unmatched mass centralization by concentrating the motorcycle’s heaviest components (engine mass, fuel tank, exhaust system and airbox) toward the center of the chassis. And speaking of the chassis, the YZ450F’s aluminum Bilateral Beam frame features new motor mounts intended to improve handling by altering the chassis rigidity balance to increase chassis feel.
Lastly, the YZ450F’s spoke wheels are shod with Dunlop’s new MX52 Geomax tires, front and rear.
2015 Yamaha YZ450F Specifications
Engine Type: 449.7cc liquid-cooled DOHC 4-stroke; 4 titanium valves
Bore x Stroke: 97.0 x 60.8mm
Compression Ratio: 12.5:1
Fuel Delivery: Yamaha Fuel Injection (YFI), Keihin 44mm throttle body
Ignition: TCI: Transistor Controlled Ignition
Transmission: Constant-mesh 5-speed; multiplate wet clutch
Final Drive: Chain
Suspension
Front: KYB Speed-Sensitive System, inverted fork; fully adjustable, 12.2-in. travel
Rear: Monoshock, adjustable preload and rebound damping, 12.4-in. travel
Brakes
Front: Hydraulic single-disc brake, 250mm
Rear: Hydraulic single-disc brake, 245mm
Tires
Front: 80/100-21 Dunlop MX52-FA
Rear: 120/80-19 Dunlop MX52
Seat Height: 38.4 in.
Wheelbase: 58.3 in.
Ground Clearance: 13.2 in.
Fuel Capacity: 2.0 gal.
Wet Weight*: 245 lbs.
Color: Team Yamaha Blue/White; White/Red
MSRP: TBA
* Wet weight includes the vehicle with all standard equipment and all fluids, including oil,
coolant (as applicable) and a full tank of fuel.
2015 Yamaha YZ250F
Yamaha’s YZ250F followed in the YZ450F’s footsteps last year with a complete redesign to incorporate an all-new, liquid-cooled, DOHC 4-valve, fuel-injected engine with the same forward-positioned straight intake, rear-inclined cylinder and rear-positioned exhaust layout as the YZ450F. The new engine drew rave reviews for its class-conquering power, and the YZ250F was a standout performer in the class. For 2015, Yamaha has made very few changes to the YZ250F.
The YZ250F’s KYB Speed-Sensitive System inverted fork specs have been changed via new fork springs, new valving and new fork outer tubes aimed toward better compliance through the mid-to-end stroke and more bottoming resistance. The YZ250F also receives the quick-release quarter-turn Dzus air box fasteners for tool-less access to the air filter.
Unlike the YZ450F, the YZ250F still rides on Bridgestone tires. It does not get the new Dunlop MX52s
2015 Yamaha YZ250F Specifications
Engine Type: 249cc liquid-cooled DOHC 4-stroke; 4 titanium valves
Bore x Stroke: 77.0 x 53.6mm
Compression Ratio: 13.5:1
Fuel Delivery: Yamaha Fuel Injection (YFI), Keihin 44mm
Ignition: Transistor Controlled Ignition
Transmission: Constant-mesh 5-speed; multiplate wet clutch
Final Drive: Chain
Suspension
Front: KYB Speed-Sensitive System, inverted fork; fully adjustable, 12.2-in. travel
Rear: KYB fully adjustable single shock; 12.4-in. travel
Front: Hydraulic single-disc brake, 250mm
Rear: Hydraulic single-disc brake, 245mm
Tires
Front: 80/100-21 Bridgestone M404-A
Rear: 100/90-19 Bridgestone M403
Seat Height: 38.0 in.
Wheelbase: 58.1 in.
Ground Clearance: 12.8 in.
Fuel Capacity: 2.0 gal.
Wet Weight*: 231 lbs.
Color: Team Yamaha Blue/White; White/Red
MSRP: TBA
* Wet weight includes the vehicle with all standard equipment and all fluids, including oil,
coolant (as applicable) and a full tank of fuel.
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