just purchesed a 1988 royal I am new to yamaha and dont know to much about them. new to internet to so my spelling will be bad. after riding for a couple days, the rpm drop to o when I am setting at a red light and it starts back firing. Give it some gas and it runs fine. It runs fine downd the road no missing or back fireing. could this be the diaphram in the carb or could it be electical. where can I find a service for it.I have been reading alot of the threads on this sight and sure helps I am glad I joined. thanks Motorhead 704