You don't need to use the choke long enough for the gauge on the needle to move that is way to long. However if you mean how long you should let the bike warm up before you take off on it then I usually let my needle start to move slightly above its starting point then I ride easy until she is up to normal operating temp. Just remember that because your water temp is up to normal operating range doesn't mean that your oil and the rest of your engine is. Especially if it is below freezing. So don't get crazy on the motor until she is good and warm all the way through.