I have a 1982 XJ650LJ Seca Turbo. I runs very smooth, but I have no power whatsoever from a standing start. I don't know what to do.

SOURCE: The turbo in my 1983

you either have a major air leak(that you would hear) or the turbo is getting a bit old.Also check the turbo oil lines.Make sure they are feeding so the turbo can spin.Hope this helps

SOURCE: 1982 Yamaha Seca Turbo (XJ650LJ) Had the carbs

Mine was stored for 20 years, I ended up replacing the seat and needles, cleaning them thoroughly and when I tried starting it, nothing!! No gas was going to the carbs, it turned out to be my gas pump, it was seized by the old gas remains 'varnish' so I had to clean it numerous times, soaked it in gas cleaner (short period at a time 15 minutes or so, being a very powerful cleaner, you cannot leave it for long without causing greater problems, thus I was able to get the pump going by boosting it with my car batterie, having more cranking amps directly to the pump, the pump was able to release itself from the old crusty varnish.