No vacuum above 2-nd gear.

[sedifus]

gz250 2000,

Got a leak, engine was shutting off.
Replaced petcock, carb hoses, rebuilt carb, both vacuum and main membrane replaced, pilot screw replaced with a new one, the pin was broken.

Now works fine in any gear as long as petcock is on prime.
As soon as it switches to vacuum ( reserve/on) it starts sputtering, but only above 2-nd gear.

Checked vacuum in neutral, it seem to work fine persisting suction. Don't know if it looses suction while in gears but no problem noticed in 1-st and 2-nd gear either.

Is there something else I could check before getting a new carb?