Help need it on NC29

[goose400]

Hello,
I'm trying to diagnose this problem:
The NC29 will start with the choke. After a while and at full choke the RPM will go up and down between 2K and 3K
-If I turn the choke off , the bike will not maintain RPM and it will turn off.
-It will start without a choke , but it will not stay on unless I press the gas and pass the 3K.
-When I press the gas, I will turn it half way with no acceleration at all and then it will accelerate quickly to 5K.
-The bike will run ok pass the 4K

I'm looking for your expertise before taking the bike apart.

-The bike had the carb clean 9 months ago, but two weeks ago I found that the small foam filter was dry and in pieces.
Could parts of the foam gone trough the airbox and clog the carburetor?
Could this be a problem that could be solve with a Carb synch?

Thanks in advance for your help.

[richyrd5]

Best bet would be to take carbs off and clean them out,as then you know it's not the carbs at fault..although it sounds like a %100 carb related problem...was it running ok before you found bits of filter in there??

[CB1pod70]

Definitely sounds like a carb problem to me - I suspect there will be bits of filter clogging the slow running jet (the long thin one)

[mechannibalism]

.....and check the air jets at the mouth of the carb, that's the first place the foam is going hit.

[goose400]

Thank you for the advice.
I will clean the carbs and report back.