The entry of the Team Marlboro Roberts Yamaha YZR500s in WERA Formula USA inspired a lot of four-stroke builders to create some of the craziest, most powerful big-bore Superbikes ever to spin up a rear wheel. The 1991 WERA GNF brought together some of the strongest challenges yet to the Marlboro GP bikes. This photo shows a few of those machines. Yoshimura R&D built a very special Suzuki GSXR displacing 1340cc, weighing in at 370 pounds and developing a claimed 200 horsepower at the countershaft. The big Yoshimura was ridden by defending Formula USA, turned AMA Superbike rider Mike Smith (No. 1). He’s leading Tom Kipp (No. 16X) on his Wiseco Yamaha OW01/FZR1000 hybrid, Kurt Hall (No. 60) on the Keith Perry-built Methanol Monster, a Suzuki GSXR1100 punched out to 1186cc fueled by methanol and Mike Harth (behind Hall) on a Dutchman Racing Suzuki GSXR1100. Smith cooked the clutch in the first F-USA leg. Hall won the first leg on the Methanol Monster, when Rich Oliver backed off his Marlboro YZR500 to preserve his motor on the series championship, after teammate Robbie Petersen’s GP bike blew up. Smith finished second to Oliver in the second F-USA leg on the big Yosh Suzuki and managed to beat Petersen in the process.