will not take trottle

[deathsshadow]

hello everyone 2009 gz 250 .. ok i have put a new throttle diapham in becuase the bike store guy said that was the problem .. the bike idles fine.. but when given throttle it dies i have taken the carb off and cleaned it so many times.. and still no change.. if i put duck tape half way over the intake hole for the air filter the bike takes throttle but doesnt let me rev out 3rd fourth or 5th gear.. i took it apart again today (the carb) and noticed the needle jet was a very small hole so i switched it with the large hole jet and at first it worked fine but then as i was down the road it stopped taking throttle again.. i had to put it in first and idle it home.. so to re cap idles fine.. will not take throttle if the air filter hole the little opening when air filter is installed properly is covered about half way it will take throttle but will not let u rev out 3rd 4th or 5th gear. the pet cock is working fine.. any ideas...