Any idea what would be causing the throttle arm on my mikuni to not return all the way? Idle will be about 1100 and sometimes it will just get stuck at 1400 on its way back down then you have to reach back there and close it the rest of the way with your hand. put wd40 on the springs and made sure that the cable on there was long enough so that it would be able to return all of the way.

Spray Corrosion X down your cable to lubricate it (let it run all the way through it). Also lubricate the pulley the cable rides on going to the carb throttle.

Heres a couple more things to look for if the cable checks out okay.

Too much throttle cable tention, easiest way to check is remove the cable from the carb sheave and see if it returns all the way closed on its own.

Or if you have recently cleaned your carb with carb cleaner it will cause the slide to stick. Mikuni sells a lube for it, but i usually just use what i have a round like 2 cycle oil.

Mine's been doin the same thing, even with the cable disconnected. For whatever reason, the slide is sticking open just a lil bit. Tried carb cleaner, but sounds like I'm about to try some oil.