If theres a hole where the lock should be, the first thing I would do is take to your police dept. to see if its stolen. If its not stolen go to the local Yamaha dealer and order a new lock for it.
Is it getting gas to the carb.,have you tired a new spark plug. do you have a full charge on the batt. If you take it to a dealer you are going to be looking at 65.00 to 80.00 an hour for them to find out whats wrong with it and that doesnt include the parts