Random High Revving

[Matt Isaacs]

Hey all,

I'be gotten my 1980 Special with original carbs running nice, except for the occasional high revving. The bike will start up at about 3,000 with the choke on, then drop to 1,000 when I take it off. But as I'm riding, it'll sometimes get stuck at the high revs after I let go of the gas. I've cleaned and rejetted the carbs with the kit from 650 Central. Could the vacuums be getting caught?

 

[gggGary]

Carbs vacuum synched? did you you a drop test on the slides. Hot water test the brass floats for leaks? Check for air leaks at throttle shafts, around intake rubbers. Spritz a bit of carb cleaner at those areas, if it revs you have a leak.

 

[xjwmx]

Sounds like air leak, could be throttle cable or something in the linkage sticking, especially the grip in cold weather. If you press the brake will it drag the revs back down to normal?

 

[gggGary]

Since you say you have an 80 XJ and I are assuming you have a TCI ignition with electronic advance, if you have a mechanical advance check for correct action of cam and springs. A timing light is the gold standard test.