why wont my f4i start

[my750]

I bought an 01 f4i that was a little beat up when i bought it. i took the tank off and a couple stunt parts and painted them. the bike ran fine before i took the parts off. i put the tank and stuff back on and it will turn over but wont start. i filled the tank half way up just incase i have to take it off again so it has gas. the fuel pump is plugged in and so are both lines leading to the tank.

Any info is appreciated