89 ex250 crazy idle issues.

[drewsley]

Sooooo here we go. Chicken house find down here in good ole Alabama. Ive pulled the carbs (12 times) dipped for a week, jets completly went through, for a fact, 2 50 yr carburetor veterans have completely went through them for me. Now. For the probz. It fires up fine, goes through it's warm up process of about 3-5?k after start up, but won't drop back to around 1300 unless I force it with the screw. When I get it to 1300 it idles juuuust fine. Now when I revv it up a bit, itll stick at 5k til I force it back down to 1300. When riding, when clutch becomes engaged it also will not drop rpm. So when I go to shift, it'll drop to 4-5k and stick. Sometimes I get lucky and it'll drop it most of the time it does not. The bike does fire on it's own, brand new spark plugs petcock and fuel filter. And I am baffled. Has anyone seen or had this problem? Or know how to attack it. I have had a few peeps look at it that aren't rookies and also have become baffled. Help would be greatly appreciated. I'm ready to put my face in the wind but dont want to ruin my 400$ purchase lol.

[drewsley]

Idle air screw Orings have been replaced as well, I have completely redone exhaust, stainless steel headers combined to one pipe into a muzzy. Currently I'm turned 3 out.

[xorbe]

5K is a looong way from 1300 ... must be getting extra air?

[drewsley]

I've been thinking that, ive even tried closing them to 2.5 turns. Same problem. Im beginning to think it's a boot issue. Its had a separator deletion as well forgot to mention that. I purchased it from a well known motorcycle guy. So I'm positive everything that was done to it was done right. But what I have done to it on the other hand is a different story. But ive made no major changes besides the petcock and orings. I could try closing to 2 turns. I also have not had them synced. I canchave that done as well.

[jkv45]

Sounds like you either have a vacuum leak between the carb and the engine or the throttle isn't returning properly.

When you say the RPMs don't come down unless you "force it back down to 1300" - what do you do?

I would sync the carbs next.

[Motofool]

Disconnect both throttle cables from the carbs and try again.

[drewsley]

To force it back down I can turn the idle knob on the left side of the carb, then adjust it back to 1300 or I can put it in first hold it still let off the clutch til it gets there and reapply the clutch put it back in neutral and release and it stays at 1300 approx. Ive tried it with both throttle cables disconnected. Same issue. One of the carb guys o had take s look at it has said he believes he hears a vaccum leak though. Ive checked all the vacuum lines, no holes odd bends cracks or anything. But also doesn't mean they aren't leaking. Just a basic check obviously. But, the little clip rings do spin freely around the tubes and dont seem like they are properly clamping the tubes.

[drewsley]

When you say vacuum leak between the carb and engine, are you implying a boot issue?

[jkv45]

Originally Posted by drewsley

When you say vacuum leak between the carb and engine, are you implying a boot issue?

Yes. Spray carb cleaner around the boots and connections and listen for a change in RPMs.

[drewsley]

Will do! I'll repost tomorrow after work when I'm able to do this. Thanks!

[drewsley]

Think ive found the problem, the clamps that go around the boot on the motor side are fully tightened but still spin around the boot.

[drewsley]

Sprayed carb cleaner around the boot, rpms went up, problem found, now to find clamps that will fit it... Thanks for everyones help!!! Knew I was in the right place. This forum is awesome!

[xorbe]

awesome work!