I actually listen for the choke to regulate, or I time the lopes. With a stock exhaust it's not to hard to tell. I expect with a modified exhaust it's even easier.
/Although, I have to say, for those in colder temps, and with the choke engaged, they must get a "good-morning" run for the first few minutes with that extra throttle response! Ihave had to run out of the house in cold weather, as many of us have, and kinda like the extra 'urmph' it gives us.
