Yamaha Seca-Turbo 650 (1982-1983)
Offering the allure of litre-bike performance in a mid-size package, Yamaha gave us the 650cc Seca-Turbo, the second of the Japanese manufacturers to offer a turbo bike. Honda had been first with its liquid-cooled CX500 Turbo, Suzuki introduced the XN85D in 1983, and the Kawasaki GPz-750 Turbo came out in 1984.
The Seca-Turbo's engine was an air and oil cooled 650cc DOHC inline-four, based on the standard Seca motor. Instead of fuel injection, Yamaha used four pressurized Mikuni carburetors. Positioned behind the motor was the Hitachi turbine unit, spinning at speeds up to 22,000 rpm. Using a stock Seca frame, the bike weighed 565 lbs. The shaft final-drive was quiet and smooth, and although it wasn't designed for off-the-line acceleration, the Seca-Turbo was capable of twelve-second quarter-mile times. The sharp-edged, frame-mounted fairing was complimented by aerodynamic tank and side panels, which blended into the seat/tail section.
Riding below 6000 rpm, the Seca-Turbo feels like any other in-line four-cylinder bike. But twist the throttle and hold on; when the turbo kicks in, it launches you down the road.
Turbo bikes never enjoyed mainstream popularity, they really weren't around long enough. Engineers were soon able to coax more power out of normally aspirated engines, which ended the need for the more expensive and complex turbos. Yamaha dropped the Turbo in 1984 in favor of their new FJ-series bike. In its two years of production, approximately 8,000 Seca-Turbos were built.