its getting colder out, so yer bike is gonna blow some white smoke out.
im not trying to say that you dont have a blown head gasket though.
when its cold out yer bike will sit over night and condensation will gather in the exhaust,so when you start it you will get white smoke. once it clears out you have no more white smoke.
so try running yer bike till you have no smoke them park it in a warmer garage and let it cool off then start it back up to see if you still have white smoke.
usually if you have a blown head gasket you will always have white smoke.
all so you will have loss compression which will result in a loss in power.
also yer bike will over heat.
you can also take yer coolant cap off yer bike and start it, if you see bubbles coming up then you have a blown head gasket or air getting into the coolant somehow.
im guessing its just cold out and yer haveing some white smoke till the bike warms up.