What is sticking - idle won't drop sometimes

[79FiveFifty]

When I got the bike it idles at 1,500. Yesterday at some stop lights it would idle at 1,000. Other times it would not idle below 2,200 or so.

I revved it up a few times and was unable to get it to drop so I do not think it is related to the throttle cable. I also choked it, which dropped the idle almost to stall speed and it went right back up with the choke off.

The previous owner told me something sticks, but I don't recall what he said.

What could it be gang?

[Steve]

Does your clutch cable go to the bottom of the left side of the engine or cross over the gearbox to the right side, under the carbs? If it crosses over, it might be catching the throttle linkage where it goes between the intake tubes.

Another, more likely, possibility is a leak or two in the intake. The boots from the carbs to the head might be loose or have a small hole. Do those boots have o-rings at the head like some of the larger bikes?

.

[doctorgonzo]

To echo Steve, lean mix is most likely culprit, leak at a boot, plugged pilot jet, leaky airbox, etc...

[Buster-boy]

I chased my tail with this and replaced everything under the sun. Had my carbs synch'd - problem solved. The problem was the #1 slide was not dropping down like it should when letting off the throttle. When this happens it keeps that one cylinder's jets open allowing more gas into the cylinders than the others keeping the r's in that cylinder higher than the others. This inturn caused 2, 3, & 4 to rise back up a bit keeping the idle at 3k. Basically #2,3,4 were fighting #1. Should cost around $100 depending where you go.

[Nessism]

Most likely these O-rings, unless you have changed them lately. I have spares for the VM carb 550's if you need some.