bike takes awhile to slow to idle speed

[stoinkythepig]

Took my old '86 Concours out for a spin today after letting it go unuded for 3 months. It did something it's never done before. When I rolled off the gas, the revs would drop slowly and then itr would barely idle. I turned up the idle speed which helped keep it from dying, but exacerbated the slow return to idle speed problem. It felt a little rough off idle but otherwise ran fine at cruising speed and made plenty of power.

Thinking vacuum leak, rodent nest in the airbox, or a torn carb diaphragm. It is not a throttle cable issue, I'm certain of that. Any other thoughts?

[Wishbone]

How about the slides (might not be the correct name but the dealies that stay closed until there is enough vacuum to open them) possibly gummed up making them close slowly and stay open a bit to much so that it is allowing to much air in.

[OreoGaborio]

that's exactly what Jenni's bike was doin. TLRman narrowed it down to vacuum leaks. Some new seals solved the problem.

[The Crashing Tomato]

I just picked up Shell's old Ex250 and had the excact same issue. +1 to fasterthana250 and Oreo. This solved the 250's bellyachin'

[beet]

Could also be your jets are dirty lean.

[stoinkythepig]

Well, finally started digging into this problem. First, I found that all 4 carburetor clamps were loose on the head side. I tightened them and it helped get it to idle properly, but it still revs with the throttle off. I can now make it stop reving by blipping the throttle with the clutch pulled in.

I took the carbs off. I cannot find any signs of vacuum leaks. I drained the bowls and used a vacuum cleaner to test the slides (suck air through the carb outlet with a vacuum, then open and close the throttle plates while watching the slides operate). The slides go up and down properly without any sign of sticking. I cleaned out the bowls, checked the pilot and main jets and am in the process of putting it back together. Fingers are crossed...

[vintage ex race]

Ck your pilot jets sounds like there is some blockage there, they have a very tiny hole so you will have to hold them up to a light to make sure they are clear. They help control the idle circuit and if they are plugged with the motor running it will start drawing fuel through the main jet circuit wich will cause the motor to rev higher

[stoinkythepig]

I ran some wire through the pilots and made sure they were clean. What ever it was, it's fixed. Runs like new now. I'm psyched. Now I don't want to sell it...

Thanks for all the suggestions and help!