You can do what re-run suggests without taking them off the bike, drop the float bowls on all four and starting on the outside one, remove the float pin (it is held in with only friction), then use a proper sized screwdiver or 10mm socket to do what he suggests. that helped me, but ultimately a bit, my 72 did exactly the same thing when I first got it running. The choke did nothing and the big symptom was that it was very hard to start and I would rev it, but it seemed to bog down at rpms, like the choke was on.
It was the carbs. Over the winter, I removed the carbs, took each one apart, dipped each one, all of the parts looked good under a magnifying glass, no pitting or grooves, so I reused it all. I got new float bowl gaskets, so all in all, it was $20 bucks for the gaskets (I probably got ripped off) plus the dip tank ($20 bucks at the auto parts store) and my own labor. There is a great how-to here:
http://www.salocal.com/sohc/tech/carb/carb.htm
The only big problem I had was getting the carbs off of the bike, I had to use a piece of wood, some hand clamps which I flipped around so they would spread the force instead of clamping. You can do it, just take your time, one carb at a time. A good time to renew the cables and check your valve clearance while you wait for the carbs in the tank.
good luck
Locked
