Motorcycle Repair: return to idle, shadow vt1100c, throttle cables

Question
Hi, I am buying a 1992 Shadow VT1100c from my brother. It has not been ridden on a regular basis in a few months. I charged the battery, put in fresh gas and fired it up. The engine is running well. The problem is after you twist the throttle it will not return completely back to idle speeds. I pulled the grip and cleaned it good and put it back.It turns real free and responds. I found on the right side of carburetor a coiled spring that is held in place by a nut. When you throttle up the spring rotates in a clockwise fashion and when you release, the springs rotates in a counter-closckwise motion bring the engine back sown to idle speed. If I push down on the spring it will idle down, but it will not return to idle speed on its own. The bike was last ridden in February. Can you help me diagnose the problem? Thanks, Gary  

Answer
Gary, high idle conditions can be caused by several things... That you can get it to idle down by pressing on the throttle cable drum, indicates that either A.. the cables need to be adjusted so you have a bit of slack at the throttle grip at idle B.. The idle speed screw needs a bit of adjusting C.. Carbs are out of syncronization .. D.. throttle cables are misrouted and hanging up slightly
E.. Carbs are gummed up inside from sitting with old fuel in them  F... all of the above.

Here's a link that you might enjoy and learn from:
http://www.shadowriders.org/

Bill Silver