bike dies in first gear..........wont rev up

hey guys, i have a new problem with my bike. i am new to bikes and have already learned alot and yall have been a tremedous help so far. i had a starting and idleing issue that i posted in the carb forum and i got that fixed with your help. hopefully you can help with this new problem.

i cleaned and tuned the carbs and replaced all of the spark plugs. now it is starting and idleing great! i took it out for a test drive today after all of the work. i rode around with no problems for about 20 minutes today. about 20 minutes into the ride i was presented with a new problem. i was in first gear and the bike just died. i started it again and it no longer will rev up. it will idle fine but as soon as i let off the clutch and try to go it just dies. if i try to give it some gas at all it just gives up on me. i dont have a clue what the problem is. i dont really know how else to describe it so if it doesnt make sense ask me some more questions.
thanks for all of help you guys have given so far.

check for a pinched fuel line.

After cleaning the carbs, was an after-market in-line fuel filter installed before allowing any fuel into the carbs?

If not, the carbs may need another cleaning.

Good Fortune!

Does your bike have a clutch or side stand kill switch? If so, one or both may be malfunctioning.