[Austins440]

So I bought an fcr off my dad for my ltz 400 and I put it on and used the 400ex intake boot and filter. When idling it runs fine but riding its boggy and will shut off. It will only run with choke on and it sputters at low throttle. I have a 165 main 48 pilot throttle is 2 clicks and fuel air screw is set 2.5 out. Maybe pilot jet is too small?

 

[amcf18]

I don't think that pilot is too small, more like something is clogged up, or you have an air leak between the carb and head.

 

[mana_z400]

does it bog at WOT? or 1/2 throttle? or just always? I'm guessing it's Accelerator Pump related,,,

Just like what @amcf18 said; Carb is clean? do you have air leaks?