Just as Yamaha has retooled the 2014 YZ250F, the 2014 YZ450F
also gets a major re-do in regards to the engine and chassis. While its unique engine configuration isn’t new for the big thumper, major engine revisions are aimed at improved engine performance while a new frame promises enhanced handling. Consider this the second generation of the rearward-slanted engine.
Originally adopted in 2010 Yamaha’s rearward tilted cylinder design was innovative, creating a more centralized mass as the heaver components of the motorcycle were moved closer to the middle of the chassis. This made for an unconventional layout of the airbox and fuel tank with the two sharing the space under the front of the seat. This gave the 2010-2013 models a portly feel at the engine shrouds. Now with a new frame and parts layout the front area has been slimmed down by 14mm.
The fuel tank of the 2014 Yamaha YZ450F is now in the center of the frame, allowing for a smooth seat and tank/airbox area.
The head tube on the 2014 Yamaha YZ450F is 10mm closer to the rider to put more weight on the front tire.
The 2014 Yamaha YZ450F is thinner at the shroud area by 14mm.
Not only did the front area lose some width but is has also been smoothed out with a flat seat that slides right up to the airbox without a gas cap in the way. The fuel tank now sits under the middle of the seat. Access to the filler cap is via an easily removable front seat section. The capacity has also increased from 1.6 to 2 gallons.
To make room for the fuel tank and to take the centralization of mass to an even greater extent, the exhaust now wraps around the engine rather than being coiled behind it. This allows for the proper length of the header while moving the silencer forward by 7.3 inches in comparison to the 2013 YZ450F
In the engine department, extensive work has been done to the top end to improve combustion and performance while at the same time adding controllability. The intake and exhaust valves have been enlarged, and the intake cam profile has been modified. The bore and stroke remain unchanged, but the piston is also new. Revised ECU settings give the YZ450F more bark off the bottom and also increase the power from 3rd gear and above. The accessory GYTR Power Tuner can be used to adjust the fuel mapping and ignition curves to suit the rider or track conditions as well.
Gear ratios have been changed on the YZ to lengthen the powerband and increase the power feel in 2nd and 3rd gears. The clutch is also new with better actuation allowing for quicker, smoother shifts from the reworked transmission.
The 2014 YZ450F’s Bilateral Beam frame is updated to accommodate the center positioned fuel tank, but also gets some tweaks to improve handling. The steering head is now 10mm closer to the rider for more weight bias on the front wheel. Overall dimensions of the frame are now similar to the YZ250F thanks to the shorter head pipe. The thickness of the frame rails is optimized for rigidity, and the swingarm bracket and middle frame rail have new shapes. Just like the 250F, the upper engine brackets are steel and the bottom brackets are aluminum.
Suspension tweaks include a new surface coating on the inner front fork tubes and the outer tubes’ rigidity has been modified. The front axle is now larger as well. At the rear, the shock’s reservoir has been moved to the left side to accommodate the fuel tank and shorter exhaust system. Both the spring rates and valving, front and rear, have been reworked for the new chassis.
Color choices are Team Yamaha Blue and a white/red colorway that sports black wheels and a gold chain. Pricing has stayed the same at $8,490, and the bikes should be found in dealerships in late June.