Red Forman

Fuel is fresh, just changed the spark plug oil filter and air filter. I've never done a carb clean or rebuild on this machine yet. can I check the timing without removing the front crank case cover? 

I have a 2003 TRX 450 FM, when I first start it runs rough and sounds like it's missing, I have to use the choke or give it some throttle just to keep it going or it will shut off. When it's warmed up it runs better but still sounds like it misses but will idle on its own. I'm not sure where to start, timing, alternator, or carburetor?