Help with carb or???

[scosgt]

2012 SYM HD 200 EVO 6000 miles.
It had a slight hesitation in the midrange.
I changed the petcock (tried both a GY6 type and a new original SYM) changed the fuel filter. Got worse.

Opened the top of the carb (Kehlin CV type) and sprayed it out. Diaphragm is intact. Got worse.

Adjusted the valves (really only two, and they were not off enough to make any real difference).

Pulled the carb and cleaned out the jets and float.

So here is the problem:
It starts instantly and idles SMOOTH. It revs like crazy on the stand. BUt as soon as I put a load on it, it bogs. I can barely hit 35 MPH, and it takes a while. Not sure if it is flooding or fuel starved.

So the very first question, is it possible to install the top parts of the carb (needle, needle seat, spring, guide, diaphragm) improperly? It does not look like it, but that is basically when my severe problems started.

Any ideas????????? Need help.