Idling way to high

[D1rtyBird3]

I put a new Nibbi PE30 carburetor with #40 pilot jet and #140 main jet and a pod filter on my bike and when I start it, it idles extremely high. When adjusting the idle screw, I have to back it almost all the way out for the idle to come down just a little and the pilot screw has to be backed out 1/8th turn. I’ve tried adjusting the throttle cable, even took the throttle off the carb to make sure the slide sits all the way down and nothing changed. Engine gets hot very fast and the exhaust was glowing red at one point. Not sure what to do? Any ideas?

[Thumper]

Originally Posted by D1rtyBird3

I put a new Nibbi PE30 carburetor with #40 pilot jet and #140 main jet and a pod filter on my bike and when I start it, it idles extremely high. When adjusting the idle screw, I have to back it almost all the way out for the idle to come down just a little and the pilot screw has to be backed out 1/8th turn. I’ve tried adjusting the throttle cable, even took the throttle off the carb to make sure the slide sits all the way down and nothing changed. Engine gets hot very fast and the exhaust was glowing red at one point. Not sure what to do? Any ideas?

What brand/model did you install this carb on?

[superjocko]

Does the engine speed up even more if you turn the handlebars to the right? If so, there's a good chance there isn't enough slack in your throttle cable to allow the carburetor slide to come down against the idle speed screw.

[D1rtyBird3]

Originally Posted by Thumper

What brand/model did you install this carb on?

It’s a Xmotos XB88

[D1rtyBird3]

Originally Posted by superjocko

Does the engine speed up even more if you turn the handlebars to the right? If so, there's a good chance there isn't enough slack in your throttle cable to allow the carburetor slide to come down against the idle speed screw.

I even took the throttle cable off to make sure the slide is all the down

[JerryHawk250]

The slide is probably installed backwards. Look to see if the slides all the way closed. If not, take it out and rotate it 180°

[D1rtyBird3]

Originally Posted by JerryHawk250

The slide is probably installed backwards. Look to see if the slides all the way closed. If not, take it out and rotate it 180°

It is all the way closed

[TominMO]

For reference:
https://www.xmotos.cz/gb/motorcycles...c-4t-2118.html

[D1rtyBird3]

Originally Posted by TominMO

For reference:
https://www.xmotos.cz/gb/motorcycles...c-4t-2118.html

Yes

[D1rtyBird3]

Originally Posted by JerryHawk250

The slide is probably installed backwards. Look to see if the slides all the way closed. If not, take it out and rotate it 180°

The slide will only go in one way, I tried to adjust the throttle cable to see if it was getting hung up and nothing changed. I took the throttle cable completely out of the carb so the slide definitely sits all the way down and the Idle is still really high. turning the idle screw counter clockwise does hardly anything until its almost all the way out. Turning the pilot screw clockwise does nothing until its 1/8th turn out.

[Thumper]

The symptoms do suggest stuck slide, and I thought that you cannot even screw on the cap to close the tower if the tab isn't aligned with the slot in the slide tower.
I believe what you are saying, the only thing I can think of causing high idle is the slide not closing all the way.
I don't think an air leak or airscrew could cause a high idle. You jetting seems in the ball park, certainly the pilot (#40). Maybe, just maybe try a #42 ??

I've gotta vote with Jerry on the slide though. It's the elephant in the room

[buzz]

My thought is put old carburetor back on, and see what happens. Bet it will work,it did before .

[D1rtyBird3]

Originally Posted by Thumper

The symptoms do suggest stuck slide, and I thought that you cannot even screw on the cap to close the tower if the tab isn't aligned with the slot in the slide tower.
I believe what you are saying, the only thing I can think of causing high idle is the slide not closing all the way.
I don't think an air leak or airscrew could cause a high idle. You jetting seems in the ball park, certainly the pilot (#40). Maybe, just maybe try a #42 ??

I've gotta vote with Jerry on the slide though. It's the elephant in the room

It is aligned with the slot in the slide tower, I did order new jets, they sould be here this evening I'll try a #42

[D1rtyBird3]

Originally Posted by buzz

My thought is put old carburetor back on, and see what happens. Bet it will work,it did before .

The old (stock) carb would only work if the choke was on, like it wasn't getting enough air and would stall when you took off choke. It also wasn't serviceable, the bowl was held on with rivets so I had to get a new carb

[J4Fun]

Originally Posted by D1rtyBird3

I put a new Nibbi PE30 carburetor with #40 pilot jet and #140 main jet and a pod filter on my bike and when I start it, it idles extremely high. When adjusting the idle screw, I have to back it almost all the way out for the idle to come down just a little and the pilot screw has to be backed out 1/8th turn. I’ve tried adjusting the throttle cable, even took the throttle off the carb to make sure the slide sits all the way down and nothing changed. Engine gets hot very fast and the exhaust was glowing red at one point. Not sure what to do? Any ideas?

Two questions, what’s the rpm of this high idle and are your valves adjusted correctly? I was concerned about that glowing red exhaust.