Jeff- firstly, you mentioned in your last post that you had choke on your unit, which makes me thik that it is a 400 single, not the v twin efi.
If so, 400's have be notorious for fouling plugs. Some have done some pilot jet changes slightly leaner. As to cold weather use, definetly switch to the 0-40w sythetic oil . And i recommend a pan heater , low wattage- 75-125 watt, plug in 2-3 hrs before need.
Hope this helps