Boosted: 1982 Yamaha Seca XJ650 Turbo for Sale

In the 1980s and early 1990s, Japan’s booming economy and fascination with innovative solutions to motoring problems led to a number of very interesting, but ultimately dead-end technologies. Anti-dive suspension, air-pressure forks and shocks, a wide range of two-stroke configurations with proprietary power-valve technologies, and a whole raft of associated acronyms to describe the aforementioned technologies. And, of course, turbocharging. Early turbocharged bikes like the Kawasaki Z1R Turbo were entertainingly crude, until they blew up, but later machines like this Yamaha Seca XJ650 Turbo were carefully designed to provide a more refined riding experience and overcome the many challenges associated with turbocharging, particularly when the technology was applied to carbureted engines like the one in the Yamaha Seca. The complex airbox had a series of baffles and reed valves to equalize and limit pressure and vacuum, the turbo was tiny, to reduce lag, and packaged between the transmission and rear wheel, instead of being connected directly to the exhaust manifold. A sophisticated knock sensor that retarded ignition when detonation was detected, combined with the low 8.2:1 compression and relatively low boost, helped to keep the engine in one piece. Interestingly, the right “muffler” is no muffler at all, and is basically a giant outlet for the turbo’s wastegate that was set to allow a maximum 7.7psi of boost. The problem with the turbo bikes like the Seca was always: “why?” At 567 lbs wet, the Turbo was a full 65lbs heavier than the regular Seca. With 90hp, it was relatively fast but, in spite of significant measures taken to reduce the dreaded turbo lag, it still suffered from the typical non-linear power delivery associated with turbocharging. Something you really don’t want to learn about when cranked over in a corner with the throttle open wide… At the time, turbocharged bikes seemed like an answer to a question no one had asked. Today, they’re a fascinating, quirky footnote with plenty of fans. I want one.