Motorcycle Repair: Dirty Carbs? & Turn Signal, yamaha fj1100, bikebandit com

Question
Jim - Thank you for volunteeering...I just picked up an 85 Yamaha FJ1100. It runs fine except after it's warmed up it throttles by itself up to 5000 rpm; I end up fighting to restrain it. Thoughts? Also, the turn signal flashes but I have to press it continously or it just turns off. I WD40'd inside the signal/horn housing but no luck. Thoughts? Many thanks.

-Rob
in Illinois

Answer
The rising RPMs at idle is a sign of a dirty or lean idle circuit. Since you just got the bike, you can assume the carbs need going over. You may try just removing and cleaning the idle jet and the idle mixture screw. That may be all it needs. Once the idle circuit is clean you can adjust the idle screw and the idle speed set to give you a steady idle.

The turn signal contact is probably corroded. You can try opening up the housing but expect alot of small parts to fall or jump out. Getting everything put back in order is a challenge. This is why the whole thing usually comes as an assembly:

http://www.bikebandit.com/houseofmotorcycles/yamaha-motorcycle-fj1100n-1985/o/m7...

Unfortunately they list it for $160 but at least its available. If it really bothers you I would try disassembling it and if you can't fit it back together you can get the NOS part or look for a used part on ebay.