sorry if this is a little off topic, but what is the benefit of removing the choke?  I have the same carb (750 though), is there a performance gain?

Most high tech carb shops will do this, but they charge more than the job is worth IMO, you want to leave about 1/8" above the air cleaner lip, not difficult with the right tools, carb obviously needs to be apart....

As far as performance, removing the choke horn is the best way to eliminate the turbulence caused by the air moving across the top of the carb. Think about a carb in a car, the carb top is inside an air filter housing and the air is virtually coming inside the carb at 360* (all the way around), now take the same carb and remove the air cleaner and the hood of the car, travel at 80 MPH, what happens? the air traveling across the top of the carb causes disturbances in the taller than the rest of the carb. choke horn, viola, there you have it, no horn, no turbulence....

GT

put a straw in a cup of water, now blow accross the top of the straw at 90*see what happens. I dont know if this applies to what your doing but you need some kind of box or scoop to presurize above the carb, horn or no horn. you can always roll like me, one horn one no horn.

Send it up if you decide to , will mill it cheap !