Has the Exup,, plugs and valve clearances been checked recently? Does it misfire before it starts? Do you use the choke when starting from cold?
It is also very possible you have water in the fuel which is common in an all weather bike.
One easy way of checking is to drain the float bowls before starting cold and then letting them refill by turning on the ignition wait until the pump stops ticking turn off the iginition andturn it one again, keep doing this until the pumps ticks once or not at all when the ignition is switch on. Then try starting it.
It is also very possible you have water in the fuel which is common in an all weather bike.
One easy way of checking is to drain the float bowls before starting cold and then letting them refill by turning on the ignition wait until the pump stops ticking turn off the iginition andturn it one again, keep doing this until the pumps ticks once or not at all when the ignition is switch on. Then try starting it.