Royal Enfield — purge valve damages

From last week my std 350 abs showed some missing after a ride of minimum 30 kms each time. I was sure that fuel level is much above reserve and realized it as some real problem, not the usual reserve mechanism. Service guys at marikar service centre, thiruvananthapuram cleaned carburetor and throttle body. But the missing started on my way to home after 25 -30 kms. Met service guys again. This time they found purge valve malfunction asked me if i had filled full tank petrol. But i hadn't done that (Though i never knew that top filling fuel in re is really a sin!!). Why to count the big tank as a merit of the bike if the rider is not expected to top-fill it?? Re should find a solution. Please...