damn i can't answer specifically but my dad has a 650 vulcan and he just put it in for the full service as it had only had oil changes done and he was informed that in the major service (which it was over due for) there are componemts in the motor that need to be changed and tightened which a simple oil change doesn't help.
But if it's just for oil top up see your local repairman they will be able to find out free of charge
