You'll want to warm it until you can take the choke off, a couple of minutes really. I wouldn't sit there and rev it either. Twins don't like to idle real long with the choke on. Don't run it hard until you see the needle on the temperature gauge go up some. With my 500 I'll fire it up with the choke on and start backing the choke off some every 30 seconds or so. Usually after about a minute of running like that it will idle smooth with no choke. Every bike is a little different though.