A common question is why motorcycle engines aren’t arranged with the air intakes in the front and the exhaust in the back. Reasons given for the usual arrangement are many but Yamaha evidently thought the straight thru approach might make sense so their new YZF450F makes this “revolutionary advancement” by turning the cylinder around, slanting it to the rear and just like that, the air goes in the front and out the back. Hmm, … imagine that.
Also interesting is the batteryless fuel injection, running off the generator.
Here’s how Yamaha describes the changes:
YZ450F’s new rearward-slanted cylinder is a revolutionary advancement that achieves unmatched mass centralization, concentrating inertial mass toward the center of the machine. This bold new design also swaps traditional intake and exhaust positions, putting the lightweight airbox and throttle body out front. This contributes to mass centralization for nimble handling while also achieving a straight intake tract for superb combustion efficiency that delivers more power.
The cylinder is offset so the connecting rod is vertical at the moment of greatest combustion force, minimizing piston friction against the cylinder wall that could rob power. That means quicker response.
The new 4-titanium valve cylinder head is matched to a fuel injection system developed specifically for the YZ450F. Instantly adapts to changing air/fuel mixtures depending on altitude and temperature, for an engine that delivers no matter what conditions.
The rearward-slanted engine allowed engineers to design straight intake and exhaust ports, creating the most direct path for air flow into the fuel-injected engine for incredible performance.
The YZ450F uses a battery-less fuel injection system with a 12-hole injector for superb fuel atomization. The 44mm Keihin® throttle body is designed for easy starting, with an integrated cold start and idle speed adjustment knob. Yamaha FI provides optimal air/fuel mixtures in all altitudes and wide range of temperatures for outstanding throttle response.
14 volt / 110W high output generator powers the battery less fuel injection system.