Never ever had this happen..
Rode an 81 XL185S for a few weeks..
At first I used the choke to start it and soon it was too rich and would not rev. So I started it without choke, one kick, and it would stay running.. with hand on the throttle.
The stranger part, it would still do it at 28 or 30 degrees fahrenheit.. wish i could get other bikes to do that..
Whats the heck is in that carb..anyway..