Welcome to the forum, hope you enjoy the company
Not sure about the bike, might just need a touch of throttle as well. Make sure the battery is well charged, clean / renew the spark plugs, balance the carbs, check the choke is actually working, etc.
Let us know how you get on.
p.s. - It's a thirteen year old bike, so it may just be acting like a typical teenager - hard to get going in the morning