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-   -   Idling way to high (http://www.chinariders.net/showthread.php?t=33989)

D1rtyBird3 03-22-2024 11:26 PM

Idling way to high
 
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 03-23-2024 02:11 AM

Quote:

Originally Posted by D1rtyBird3 (Post 405944)
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 03-23-2024 05:41 AM

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 03-23-2024 06:44 AM

Quote:

Originally Posted by Thumper (Post 405947)
What brand/model did you install this carb on?

It’s a Xmotos XB88

D1rtyBird3 03-23-2024 06:45 AM

Quote:

Originally Posted by superjocko (Post 405950)
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 03-23-2024 07:15 AM

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 03-23-2024 07:31 AM

Quote:

Originally Posted by JerryHawk250 (Post 405954)
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 03-23-2024 08:25 AM

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

D1rtyBird3 03-23-2024 10:03 AM

Quote:

Originally Posted by TominMO (Post 405958)

Yes

D1rtyBird3 03-23-2024 10:09 AM

Quote:

Originally Posted by JerryHawk250 (Post 405954)
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 03-23-2024 10:32 AM

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 :wtf:

buzz 03-23-2024 11:09 AM

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

D1rtyBird3 03-23-2024 11:56 AM

Quote:

Originally Posted by Thumper (Post 405962)
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 :wtf:

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 03-23-2024 12:00 PM

Quote:

Originally Posted by buzz (Post 405965)
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 03-23-2024 12:46 PM

Quote:

Originally Posted by D1rtyBird3 (Post 405944)
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.


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