The horse-and-rider relationship of a jockey and thoroughbred is the bond I felt piloting Kawasaki's Ninja 650R motorcycle.

A 1,000-pound racehorse is a living, breathing animal. At 393 pounds, so is the Ninja.

Of course, a thoroughbred costs tens of thousands of dollars to acquire, if not more. You can stable the 650R in your garage for $6,499, and it's cheaper to feed and maintain.

The manufacturer groups this motorcycle among its three street bikes, which include the popular 250R, updated in 2007, and the 500R. And like those two bikes, the 650R, introduced in 2006, unabashedly takes cues from Kawasaki's speedbike line.

It acts like a racehorse, impatiently keeping pace on busy city streets. Show it the crop and it perks up. Then dig in the spurs and hang on. The fuel-injected, liquid-cooled, 649cc parallel twin engine is ready to gallop.

The ability to pull away from traffic in any of the six gears, like the Lime Green paint on the tester, gets your attention. It's a middleweight with heavyweight street cred.

I learned to respect its kick after passing traffic on state Route 76. When an opening presented itself near the Pala Casino, I rolled on the power and the bike shot to 80 mph in third gear almost instantly. What really was scary - and impressive — is that the bike was still 3,000 rpm below the 11,000 rpm redline. Two-piston-caliper dual petal disc brakes in front and a single-piston caliper on the rear petal disc would have provided plenty of stopping bite if needed.

The Ninja, in a bow to the supersport Ninjas, maintains aggressive styling. The full fairing pushes the air to about neck height, which caused some buffeting at my head but was not unpleasant. The footrests are set slightly to the rear, which forces the rider to lean slightly forward. It's not uncomfortable, just different.

Those who are not accustomed to riding position, 31 inches off the ground and with knees slightly raised, tend to place all their weight onto the grips, which quickly fatigues the wrists. But the Ninja's seat is 8 inches wide at its narrowest point. You hug the bike with your knees and use your legs to lean the bike into turns and take pressure off the wrists and hands. Using your lower body complements the slight directional inputs needed with the tubular handlebar. You guide the bike more than you steer it.

The exhaust is nicely stashed on the lower right side. It's not an ugly canister stuck on a pipe on the rider's flank and pointing up to the sky, like someone took your mom's old tank vacuum and attached it to your ride.

Kawasaki boasts about the 650R's credentials as a commuter transporter, and it should. The test bike squeezed 50.2 miles per gallon out of the 4.1-gallon tank. But a softer seat would be advisable for commutes farther than 30 miles. Three hooks are under the passenger seat for straps or bungee cords to secure cargo.

The powerful Ninja might not be the best choice for a beginning rider, but it would be a good acquisition for someone moving up in engine size. Among the other Thoroughbreds in this class, the $6,499 Ninja is a winner right out of the starting gate.

SPEC BOX

Engine: Four-stroke, liquid-cooled, DOHC, 649cc parallel twin with four valves per cylinder

Horsepower: 71

Transmission: Six-speed

Wheelbase/length: 55.5/82.9 inches

Front suspension / wheel travel: 41mm hydraulic telescopic fork / 4.7 inches.

Rear suspension / wheel travel: Single offset laydown shock with adjustable spring preload / 4.9 inches.

Tires: 120/70x17 front; 160/60x17 rear

Brakes: dual 300 mm petal discs with two-piston calipers front, single 220 mm petal disc rear with single-piston caliper

Seat height: 31.1 inches

Dry weight: 393 pounds

Fuel tank: 4.1 gallons

Colors: Lime Green, Sunbeam Red, Metallic Diablo Black

MSRP: $6,499, with 12-month warranty

Joe Taylor writes about automobiles for The San Diego Union-Tribune. Contact him at [email protected].