Predator 212 (non hemi) idling super rough

[RodKimble04]

I just got my first mini bike, has a stock (to my knowledge) predator 212 only a year old, and centrifugal clutch. Motor looks to be in great shape. Previous owner had it sitting inside for months on the bike.

it was idling incredibly rough so I ordered a new carb and replaced it…same problem. I have tried the air/fuel mixture screw adjustments and nothing helps.

when I open up the throttle it bogs down and idles really rough before gaining speed and smoothing out to run completely normal

what could it be? I’m going to try and replace the fuel filter tomorrow because idk if it’s any good. Does anyone know what it could be? It runs great at higher rpm/speeds. Could it be the clutch spinning when it’s not supposed to and putting load on the engine??

 

[RodKimble04]

I’ll also ad that the engine makes a strange sound that’s sort of like a hiss when idling and pretty loud

when I installed the new carb I made sure to put the seals on so i don’t think it’s a vacuum leak??

 

[Augiedoggie]

Your description of symptoms is screaming vacuum leak. Spray some aerosol carburetor cleaner near hissing noise while engine is running. This can help isolate leak area. Try not to spray on hot exhaust. Probably a good idea to check valve clearances as well.

 

[sparkwizard]

Check the plastic spacer that goes on before the carburetor. It could be upside down, missing or cracked.

 

[RodKimble04]

Cool I’ll check those things

when I give it throttle at idle it kills it. If I ease on it it’s okay but if I open it up it dies.

 

[sparkwizard]

Is it full of gas? Is there water in the tank?

 

[RodKimble04]

Is it full of gas? Is there water in the tank?

Yes it’s full, checked that and put new in when I got it because the old was really old.

maybe it’s plugged filter…still gotta check, I’m so lost