Once you have checked whether the charing system is working or not if it is ok and you still have problems then just a thought
Using the stock cv carb in this part of the world i can suffer from carb icing symptoms are backfiring rough running and engine cutting out if i leave bike for a wee while heat from engine melts the ice and i am good to go for a while
the bad running is caused by a weak af mixture as the slow jet is first to ice up
although in your area i would not expect carb icing but dirt in the fuel system and or a partially blocked carb, filter or pipe may caused reduced fuel flow
Brian