Recently bought an '85 VF500f, starts up just fine in the summer heat with little/no choke, idles around 1300rpm until it warms up, then after riding begins to idle high, around 2k. Suspecting this is an issue with the choke, as turning the handlebar choke lever opens up the choke smoothly (choke on), but pushing the lever back meets with very little resistance and doesn't seem to close the choke lever, as when I push the lever back while looking at the choke valve, the valve stays in the extended position, but I can push it back in with my finger (though with a bit of effort). Furthermore, when the bike is warmed up and idling high, keeping my finger pushed on the choke valve will drop the engine to about 1500 rpm, but as soon as I lift my finger off the valve the revs climb back up to 2k. Three possibilities I've considered are: 1. Choke cable needs lubing. 2. Choke cable needs adjustment. 3. Carbs are gummed up and preventing choke valve from fully closing Any suggestions on what to try first? Would like to avoid pulling the carbs until the end of riding season if possible.
You need to test the cable while it's disconnected to check for stiffness or binding and probably clean carb choke port and the plunger too. Maybe a free-play adjustment would help. Lever should have no resistance for a few mm or it's too tight. Cable adjustment is up under the left switchgear. Read the FSM.
Thanks, have been reading the FSM but didn't get quite the detail I was looking for on how to adjust and test the choke cable. So I should disconnect the cable on the carb end to test for stiffness and binding?
That's right, and be super-carefull not to loose the small brassy-looking spring in back of the plunger. Matter of fact, if one of those went AWOL, it could cause your problem.
Spraycan carb cleaner, but keep spray away from any plastic. Scotchbrite to polish up the choke plungers. one quick spritz with WD-40 when assenbling.
