The cutting edge cuts both ways and sometimes a little too deeply. The Honda CBR600F4i, the first fuel-injected 600cc sporty four from Honda, debuted in 2001 and quickly found a place in the hearts of riders who wanted a dash of practicality with their thrills. Then, in 2003, Honda dropped the CBR600RR into the churning dogfight that was the middleweight class at the time, and the F4i found itself overshadowed by its newer, feistier, more razor-focused sibling. Subsequently the Big Four knocked themselves out upstaging one another with 600s that increasingly traded street utility for track supremacy, relegating the CBR600F4i to the nice-try bin. It was discontinued in 2006 but remains a favorite among connoisseurs of middleweight versatility.

It’s a stretch to say any engine with a 14,200-rpm redline has a broad powerband, but compared to the other 600s in the class the F4i was easier to ride off the cams, starting to pull hard at about 6,000 rpm. Once on the boil, its four-nozzle fuel injectors and 38mm throttle bodies helped increased horsepower by about 5 over its carbureted predecessor, the F4. Even at lower revs throttle response was exemplary for the class. A larger rear sprocket and a shorter sixth gear provided added acceleration on top, handy for passing without downshifting.

The F4i’s seating position, with clip-on bars mounted above the top fork clamp, was less contorting than other bikes in the class. In ’04 the split seat was replaced by a one-piece “banana” seat, but neither made a lot of friends among sport-tourers; both encouraged roadside pit stops before the 4.8-gallon tank needed refilling. Numerous small weight savings, notably to the brakes and wheels, shaved about 4 pounds off the F4i’s weight compared to the F4, and a stiffer chassis contributed to handling that was direct and immediate yet reassuringly stable. Braking wasn’t quite up to the class standard but only if you’re picking nits; for real-world riding the bike had plenty of whoa power. A redesigned fairing accounted for a small reduction in drag compared to the previous model and gave the impression of sitting in the bike rather than on it, a welcome dollop of creature comfort that offset the awful seat.

The Honda CBR600F4i is like a lot of other popular sportbikes in that bone-stock used ones are hard to find. Don't panic if one headlight seems to be burned out; only the left is on in normal running, with the right coming on only when you hit the high beams. A rattle from the engine at certain rpm is likely to be the cam-chain tensioner. Although it sounds bad, it rarely harms the engine; most riders swap in an aftermarket unit. Charging problems are sometimes traced to burned-out regulator/rectifiers, starting issues to the fuel-pressure regulator. Aside from the pain in your wallet both fixes are simple and straightforward. Otherwise the F4i is renowned for its reliability. That doesn't mean you don't want to ask for service records, and check the bike for mismatched bodywork, pegs, and levers that can indicate a crash in the bike's past.

Less rigor, more vigor. No need to suffer for your fun.

Not as sharp-edged as its contemporaries. Hard seat limits touring.

Engine rattles, hard starting due to charging, or fuel-pressure issues.

Sporty, versatile, reliable. The Gentleman’s Express of the early 21st century.

2001 / $2,550 2002 / $2,820 2003 / $3,130 2004 / $3,465 2005 / $3,815 2006 / $4,225

Kawasaki's familiar and successful carbureted ZX-6R was so good it took two machines to replace it. Sort of. Actually, with this new generation of sportier, more serious ZX-6R, you got a choice of the standard street model, now displacing 636cc, or the ZX-6RR, with a short-stroke 599cc engine for supersport racing. The last ZX-6R (for awhile) with a low exhaust, this generation was a strong performer whose midrange torque benefitted from the extra displacement.

Introduced at the same time as the mighty GSX-R1000, the 600 shared its bodywork, basic frame, and many other details with the rest of the three-member Suzuki GSX-R lineup. Lighter and more powerful than its carbureted predecessor, the third-generation 600 was raced successfully and became the go-to machine for young sport riders. Crashed early and often though.

Matching Kawasaki as a latecomer to fuel injection, Yamaha's high-revving, dramatically small middleweight put down a lot of power—more than 120 hp at the crank or about 105 at the rear wheel—very effectively. Even better, it combined that top-of-the-tach rush with reflexes so quick you'd almost call it jumpy. Experts loved the Yamaha's aggressiveness. New riders not so much.