The Best Inline-Fours Of Yesterday And Today

Of youthful folly, rice burners, and the gold standard of speed

inline-four development
Pictured is 30 years of inline-four development side by side.Kevin Wing

The first chapters of my road biking history are about teenage bravado, rushes of adrenaline measured by the distance between an apex and an open throttle, and of inline-fours.

Drenched in the golden light of nostalgia, my memories are of grinding away a CBR600F4i’s peg feelers like a pencil eraser scraping across a sheet of homework; of redlining it through the gears on a 2000 R1 on deserted country roads; of tempting the galaxy-spinning, dare-you-to-keep-it-pinned speed of a GSX-R1000 K5; of scraping in virginal knee sliders to the soundtrack of a GSX-R750’s airbox howl. To be 17 again—when time passed at 14,000 rpm, youth kept wisdom at bay, and Valentino Rossi rode a Honda V-5.

Naming “the best” inline-four sportbike is like trying to decide on a favorite beverage. Water? Coffee? PBR? Am I thirsty, in need of a boost, or at a frat party? I can cross the last one off the list, anyway.

It’s a shame that inline-four sportbikes have garnered an ignominious reputation in some circles. Too often, non-riders refer to them as “rice burners” with a tinge of disdain in their voices. Inline-fours are, after all, the gold standard of sportbike engine configurations because they’re so damned good.

When Honda introduced the CB750 it felt like cheating. Compared to its pushrod twin competition, the CB’s performance was a revelation. It wasn’t the lightest or sportiest bike out there, but its reliable four-cylinder engine made finding higher horsepower and higher revs the wave of the future.

Inline-fours tend to be vibe-y and require a balancing shaft to smooth things out, and in some cases, you can practically spread a tablecloth over their big block of cylinders in the frame, but there’s something so rock ’n’ roll about a quick-revving four that shrieks to high heaven. In the words of AC/DC, “Rock and roll ain’t noise pollution.”

In addition to inspiring memories of days gone by, the inline-four is one heck of an efficient way to make power. Besides, 30 years of GSX-Rs, half a century of CBs, a preponderance of ZXs, and just as many YZFs can’t all be wrong.

Yesterday: Yamaha TZ750

Yamaha TZ750
Yamaha TZ750Jay McNally

When race fans recollect past eras of racing, it’s often accompanied by wistfully staring off into the distance and uttering some platitude, like: “Those were the days when men were men.” It’s easy to romanticize the past and I’m not opposed to indulging in it as long as we know that’s what we’re doing. So “back when men were men…”

Most 750cc two-stroke racebikes, like the Yamaha TZ750, had traction-breaking, light-switch powerbands that made getting through a corner without high-siding a game of chance. Either that or it was the proof of freakish ability. Racers were rodeo riders and their crew chiefs were mad scientists.

Kevin Cameron recalls, “When the AMA series got to Talladega, many big TZs were frighteningly unstable at speed. I saw more than one rider take to his lawn chair white-faced and shaking.”

The TZ750 was Yamaha’s first inline-four racer designed for 750cc production class racing. The TZ750 was such a potent weapon that it practically filled the entire grid at Daytona. It was the bike that lured Giacomo Agostini over to Yamaha and the dark side of two-strokes. The smokin’ TZ was ridden masterfully by the likes of Yvon Duhamel, Kenny Roberts, Steve McLaughlin, and a score of legends. Did the TZ750 make the legend, or did the legend make the TZ750?

Today: Yamaha YZF-R1M

2015 Yamaha YZF-R1
2015 Yamaha YZF-R1Yamaha

The Yamaha R1 has been a literbike legend since it was first unveiled prior to the new millennium. The current model does the R1 badge proud. We love that Japanese literbikes, taking a cue from the European competition, are available in up-spec versions, such as the R1M, which adds full carbon-fiber bodywork, electronic Öhlins suspension, and a polished aluminum gas tank to the base-model R1 and R1S.

The R1M retains Yamaha’s crossplane crank concept, which places crankpin spacing at 90 degrees instead of the more typical 180 degrees. In 180-degree cranks, the pistons are simultaneously stopped every 180 degrees, which means the crankshaft’s rotational velocity is non-constant. Practically, the engine’s power pulses are thought to improve traction and drivability.

The crossplane crank also sounds like a small-block Chevy engine. No one will mistake the R1 as a 600cc “rice burner.”

Obviously, the Kawasaki ZX-10RR is cleaning up in WorldSBK, the GSX-R1000 in MotoAmerica, and the BMW S1000RR and CBR1000RR remain perennial favorites. Feel free to disagree with our pick. Comment below.