LTR450 won't start! Please Help!

I have a 2006 Suzuki LT-R450. I can't start my quad and i don't want to take it to the dealer because they'll charge me a bunch just to inspect the thing and then ill have to pay more for them to actually fix it. I DO NOT have a lot of money and was thinking maybe one of you guys can help me out. I don't remember how it all started but when i try to start my quad it doesn't want to turn on and when i do turn it on (push starting it) it shuts off on me when im not constanly on the throttle giving it gas. Its electric start and when i hold the clutch in, put it in neutral, and push the start button it'll sound like it wants to start but wont. It'll even backfire a couple times. I checked the fuel line and its on, the battery is good (obviously) and i don't know what to do. Changed spark plugs, oil, brake pads, lubed the chain and washed it. Its been like that for almost a year and i still ride it but i dont go out as much because i keep thinking of how im going to have to push start it and hope it wont shut off on me etc. It has a cherrybomb and yoshimura exhaust pipe. Please help me out if you can. Im really looking forward to going to the dunes and forest's but second guessing the trip because of the problem. I just want my baby to work again.