150cc Doesn't run right with intake/filter on
 

I bought an SNL 150cc
I replaced the carb and some other components as it did not run.
Got it running and noticed with the stock intake (and the new nibbi tube and cone filter) it hesitates when it gets around 30-40 at full throttle.
I tried to adjust the carb and can get the hesitation to move up to 40 but can not get it to go away.

When I remove the filter and tube and run just the carb it runs great

I have little choices in intakes and filters because i have the cross member the intake has to go under. I could not install the nibbi intake manifold its too long
and the carb his the cross member.
I am wondering if its the slide in the carb that opens with airflow.

I would go with another carb but because of this cross member I'm not sure what will fit. I could turn the carb around and face forward, then i'm very limited on space. I can't find pictures of other people with this cross member seems many have an open area

this is the crossmember
https://i5.walmartimages.com/asr/f9f...2&odnBg=FFFFFF

What happens if you run the stock airbox and stock filter?

same result.

I bought new stuff because i first thought it was the stock intake tube possibly collapsing.

Make sure the diaphragm is fully seated in the top of the carb