My bike has been running fine until last month. It use to start just fine, then I would start it and it would die if I didn't use the choke for a couple of minutes, now it won't start at all. I can smell gas so I know it is getting gas plus it is backfiring a lot which means it is getting spark. No gas is leaking out so it doesn't seem like it is majorly flooded or anything but when I say it backfires a lot I mean it backfires A LOT. I have gotten it running twice in the last 2 weeks and let it idle but after shutting it off and trying again a couple of hours later, it won't start again. Any suggestions?