1984 Yamaha RZ350 Kenny Roberts Edition, Frame no. JYA48H002EA000894 Engine no. 48H000894

1984 Yamaha RZ350 Kenny Roberts Edition
Frame no. JYA48H002EA000894
Engine no. 48H000894
• Rolling tribute to an American racing legend
• Last of the two-stroke pocket-rockets
• Engine and electrics completely restored
• Aftermarket expansion chambers and stock exhaust included

It is entirely fitting that the Yamaha RZ350 would be the last legal two-stroke streetbike sold in the U.S. in the face of ever-tightening EPA regulations. With a sporting history going back to the R5 of 1970, Yamaha's 350-400cc pocket-rockets had always been among the best and brightest of the strokers, giant-killers on both backroads and race tracks.

Outwardly simple, the RZ's six-speed, 347cc parallel-twin needed some technical assistance to sneak past the U.S. government's exhaust sniffers, namely a two-stage catalytic converter in each muffler, the first time this technology had been applied to motorcycles. Also making its debut on the street was YPVS, Yamaha's race-derived, electronically controlled variable exhaust port system, meant to broaden the engine's powerband. Likewise, the RZ350 was among the first roadsters to use a perimeter-style frame, now common fare for sportbikes – albeit crafted from aluminum beams rather than the RZ's round steel tubes.

Cosmetically, the RZ350 was a knock-out, a rolling tribute to Yamaha factory racer Kenny Roberts, two-time AMA Grand National Champion, three-time Daytona 200 winner and three-time 500cc Grand Prix world champion, then still at the height of his road racing powers. It was "King Kenny" whose race bikes first carried Yamaha's signature black-and-yellow bumblebee paint scheme, officially known as "Speed Block" and originally designed by noted graphics artist Rollin "Molly" Sanders. Just to drive home the point, decals of Roberts' signature were affixed to each side of the bike's bikini fairing. Cycle World was the first magazine to road test the Yamaha, hardly a clandestine endeavor as it turned out. "It became an everyday occurrence to be swarmed by curious people whenever we parked the RZ," said CW. "If good looks could kill, the RZ would be the atomic bomb of motorcycles."

Noting the bike's intended purpose was to "straighten out curvy roads in an almost effortless manner," the magazine quite rightly pegged the RZ350 as a harbinger of the single-purpose sportbikes about to inundate the marketplace: "All of this adds up to a motorcycle with an unusually narrow focus, a lightweight repli-racer sport machine. And within that narrow scope, the RZ350 is so good, so right."

When acquired by Marbles Motors, this RZ350 was complete but in need of considerable attention. The engine was completely disassembled and rebuilt from the crankshaft up. Electronics, including the power valve system, were gone through, with parts rehabbed or replaced as needed. Brakes were overhauled. Carburetors were cleaned and fitted with new needles/jets tuned to the aftermarket Spec II expansion chambers (a good set of OEM exhaust pipes is included in the sale). Citing a few small imperfections in the original paint, the shop, known for its high standards, rates this Roberts Replica RZ as a solid 9 out of 10.