Handlebars: The Littlest Ninja Gets a Stiff Shot of Power

WHAT IS IT? A serious small-bore sportbike suitable for beginners and veterans.

HOW MUCH? $5,119 as tested, $5,819 for the model with antilock brakes.

WHAT MAKES IT GO? A liquid-cooled fuel-injected 296 cc 2-cylinder engine.

ALTERNATIVE 2013 Honda CBR250R, $4,509.

It’s not much more than the volume of a shot glass, but the 47 cubic centimeters of displacement that Kawasaki added to the engine of its smallest sportbike makes an amazing difference.

The bigger engine powers the 2013 Ninja 300, a redesigned and hopped-up successor to the company’s longtime entry-level Ninja, the 250R. Although engine size grew less than 20 percent between the two models, horsepower and torque made bigger gains. The effect of the added power, and the way it is delivered across the r.p.m. range, make the Ninja 300 a much more satisfying ride than its predecessor.

Other welcome upgrades combine to make this a bike that will put novice riders at ease. A new slipper-type clutch operates with a very light pull at the lever, and it is forgiving should you forget to match engine revs to road speed when downshifting, an oversight that, with a conventional clutch, could cause the rear tire to break loose. The narrow engagement range of the clutch takes a little getting used to, though.

A manageable 379-pound weight, and a seat height that lets a rider with a 30-inch inseam easily reach the ground, contribute to the feeling of confidence and control.

Ninja 300 riders on a budget will also appreciate the absence of decals or graphics announcing the engine size, making it possible that onlookers would take it for one of Kawasaki’s bigger — 636 cc or even 1000 cc — Ninjas. Nobody’s the wiser.

My test bike was painted Pearl Stardust White, prompting me to nickname it “the nurse.” Whose idea is it to paint motorcycles white these days, anyway?

Small high-performance engines make their power by spinning at high r.p.m., moving lots of fuel and air through their cylinders every minute. In the Ninja’s case, this translates to a limit of 13,000 r.p.m., where the rider will be spending a lot of time because it feels so great.

But now there’s also useful power available from idle through midrange, a span where the Ninja 250 fell short. While 250 riders found themselves shifting gears at 9,000 or 10,000 r.p.m. to accelerate with traffic, 300 riders get by revving the engine far less.

That benefit did not come at the sacrifice of high-speed performance. Keeping pace with 75 m.p.h. traffic on an Interstate, the 300 will accelerate when you open the throttle, letting you stay in sixth gear, where the 250 needed a downshift. It’s even possible to judiciously pass a slower vehicle on a two-lane road aboard the 300.

Kawasaki engineers achieved the power increase by lengthening the piston stroke by nearly eight millimeters, bringing the engine displacement to 296 cc. They also replaced the carburetors of 2012 models with responsive electronic fuel injection using larger-diameter throttle bores, revised the inlet passages and installed bigger intake valves. An increase in the diameter of the exhaust plumbing also improves engine breathing. Not only do these changes improve power output, they have actually increased fuel efficiency too, Kawasaki says.

With its overall redesign and added power, the Ninja 300 pulls away from its closest rival, Honda’s well-liked single-cylinder CBR250R, introduced for 2011. The Honda arrived on the market delivering the low- and midrange power the Ninja 250 lacked, making it easier to ride and winning fans. But the Ninja 300 has 35 horsepower at the rear wheel, according to tests by Cycle World magazine, surpassing the Ninja 250’s tepid 25 horses and the Honda CBR250’s 24 — a decided edge.

Riders with decades of experience on much more powerful bikes often come to appreciate the appeal of light, lithe bikes that can dive into curves at brisk speeds. That’s exactly where the Ninja 300 is stable and inspires confidence, a bargain when calculated in terms of thrills per dollar. STUART F. BROWN