2013 Kawasaki Ninja 300 | Small Bikes Rule!

Going Big in the Small Bike Class

By Marc Cook, Photography by Kevin Wing

They say: “The ultimate lightweight sportbike!”
We say: “There is a replacement for displacement.”

Kawasaki is just following tradition here. Upon seeing Honda’s CB750 in the late 1960s, Team Green changed course and kicked out the 903cc Z1. A year after, the largest two-stroke streetbike was a 305, Kawasaki dropped the H1 onto the scene, a brutal 500cc triple, followed four years later by the insane 750cc H2/Mach IV. A decade ago, the company “cheated” with the ZX-6R, which boasted a 636cc engine—and it’s set to do it all over again this year.

Kawasaki followed this proven path once more, seeing it as one sure way to answer the common complaint of small motorcycles: lack of usable, street-ready power. That’s how we get the Ninja 300, a bike without a displacement class. (Actually, it has one; in countries with tiered licensing, the same bike will be available as a 250.) Why a 300? Several reasons, starting with the fact that the existing parallel-twin engine could be expanded this far without an expensive redesign, and ending with smart marketing. The 300 needs room between it and the Ninja 650; building it as a 400 or 450 would cramp the categories.

To get the smallest Ninja’s power out of the basement, Kawasaki committed a substantial rework of the 250R’s engine, though it kept the basic architecture. Pistons travel a longer stroke, 49mm against the 250’s 41.2; the bore remains 62mm. Kawasaki went to lighter, Alumite-coated pistons so it could retain the old 13,000-rpm redline. Shorter connecting rods accommodate the increased stroke so the engine’s overall height remains the same. Other bottom-end changes include a revised counterbalancer with dual weights that are thicker, 4 percent heavier and 10 percent further from the shaft axis.

For every Ninja 250R owner who wailed about cleaning or jetting carbs, there’s this: Move up and get a dual-valve electronic fuel injection system instead. In place of the 30mm carbs are throttle bodies with 32mm primary butterflies (directly controlled by the rider) and 40.2mm secondaries. They feed larger intake ports that end in 1mm-smaller intake valves. These changes, alongside the lowered compression ratio, down a full point from 11.6:1, and exhaust header with longer primary tubes, show that Kawasaki was looking to increase maximum power through displacement and boost midrange torque through a specific state of tune.

Were these efforts successful? Oh, you bet. On our SuperFlow dyno, the Ninja 300 pounded out 33 horsepower at 11,000 rpm and 16.9 lb.-ft. of torque at 9800 rpm. Compare that with the last Ninja 250R we had, which moved the needle to 24.7 bhp at 10,250 rpm and 12.8 lb.-ft. at 9500 rpm. It almost seems like the 300 is peakier, but it carries at least a 4 bhp advantage from 4750 to 10,250 rpm. It’s the area under the curve that counts: Overlay the charts and you’d swear the difference was more than 47cc.

It’s as good out on the road, too. The 300 idles smoothly but revs with a diminutive roar, a small person with an unexpectedly gravelly voice. Pull in the very light clutch—its springs are softer because of a combined slipper/assist design that improves clamping force without abusing your left hand—select first and it’ll pull away with just a handful of revs. The Ninja feels like it has less flywheel than the single-cylinder Honda CBR250R, so it takes a bit more throttle to maintain revs once the clutch bites, but then it starts to make instant headway. Adequate power comes on as low as 3000 rpm, but then starts to pull smartly by 5000. All of the fun lives between 9000 and 12,000 rpm—there’s a noticeable flattening of power near the redline—but if you find yourself anticipating poorly and try to exit a corner at 5000 rpm, it’ll still pull up onto the powerband. Try that on the 250 and you’ll be looking to see if you’ve mistakenly planted your boot on the brake pedal instead of the peg.

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