Bought a 2003 rev 3 200cc on friday , going well. Went to ride it today , got 10 mins on main fuel position then starved itself and died (tank was full , choke off) . No kicking would start it. 
Put it to reserve tap position , runs a dream , for as long as i like (running it on main position starves itself after 10 mins) .  
2 problems .... 
1 : If i run it continually on reserve it leaks from the carb (might do the famous mods stikied here) (However when it runs for 10 mins on main it doesnt leak ....) 
2 : it wont run for more than 10mins on main position. 
Is it just the carb or is the fuel tap knackered ???? 
Thanks