Lifan 140cc idle/reving problem?

[TNGclips1]

Ok so i bought a lifan 140cc from a guy secont hand to put onto my 110cc chinese frame. All went well but when i get it started it idles ok but when I rev it kind of delays and keeps revving when I take my hand off the throttle. Ive adjusted the carby and searched tutorials but nothing. Here is a video of what it is doing: Lifan 140cc carby issue - YouTube.

Please tell me whats wrong with it.

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[gottagetacheaperhobby]

Did you rejet the carb to suit the extra cc's?
Have you made sure the cable isnt snagging and holding the slide open?
Might also pay to check inlet manifold is sealed properly, a spray with wd40 while the engines running will tell you if you have a airleak. Spray where it bolts to the head, if the rpm changes then you have an airleak and need a new gasket
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[TNGclips1]

Did you rejet the carb to suit the extra cc's?
Have you made sure the cable isnt snagging and holding the slide open?
Might also pay to check inlet manifold is sealed properly, a spray with wd40 while the engines running will tell you if you have a airleak. Spray where it bolts to the head, if the rpm changes then you have an airleak and need a new gasket
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It a new carby that i bought for it a 26mm

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[gottagetacheaperhobby]

Chinese mikuni or oko?

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[TNGclips1]

This one: PZ26mm Lever Choke Carby Carburetor 125cc 140cc PIT PRO Trail Dirt Bike ATV Quad | eBay

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[gottagetacheaperhobby]

Ok, its a china knock off of the mikuni, can be a prick to tune due to the air fuel mix screw being under the carby. Pull the bowl off and see what pilot and main jet it has in it...

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[TNGclips1]

Thanks mate got it to work properly. I took the carby and manifold of and reseated the gasket and put it back togeather. Also changed the angle of the carby using the spinner. Now its running amazingly well. Cheers

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[Kingkerm1976]

Ok, its a china knock off of the mikuni, can be a prick to tune due to the air fuel mix screw being under the carby. Pull the bowl off and see what pilot and main jet it has in it...

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Looking at 26mm Nibbi carburetor for my yx140cc build has anyone tried one

 

[Kingkerm1976]

Looking at 26mm Nibbi carburetor for my yx140cc build has anyone tried one

 

[Kingkerm1976]

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