Did you try to push start it in 3rd gear? get back on your downhill cause it easier and click the RM up into 3rd, pull the clutch in, one of you get on bike and the other push it down hill. then just let the clutch out and it should turn the motor over with out causing the rear wheel to slide. You need weight on the rear end and a higher gear to keep the tire from sliding. If the bike doesn't start immediately and the "pusher" is up to it, have him keep pushing the bike as far as he can. sometimes they won't start instantly but will 10 or 15 feet later. If you ride the bike at least once a week, i see no need in draining the carb. If it's going to be stored for a while, when you go to put it up, just turn the gas off and let it run until the carb bowl runs out. then it should start easier next time.
Also you might try this. If you cant start it by kicking it, then turn the gas off and put the choke on. hold it wide open and kick it over several times. If it fires great, if not then turn the gas back on, turn the choke off, and do not give it any throttle and kick it over.
just a couple ideas that I used to use! Good Luck!
1986 Tecate
1984 Tecate
1985 Tri-Z
1986 ATC350X
1985 ATC250R (2)
1985 ATC125M (2)
1982 ATC70 - Original Owner
175 TriMoto Frame with Pro-Tec Rear Suspension
3-Wheelin' since '82