Another way to get an easy start is put 70% or 91% Rubbing Alcohol in a windex type sprayer. Spray 2 squirts on the air filter and take off. This is better than putting a large amount of alcohol in the fuel (ISO HEET) or using Gas-o-hol. You can get small sprayers in the travel goods/cosmetics dept. of dollar and dept stores.
Someone asked about this. It doesn't take much, and you shouldn't need to full-choke the bike if you spray it. (you might flood it with the regular fuel)
If you can shroud the air filter from the cold, with a foam wrap on the paper/fiberglass element, you might also have better luck. It works well for lawn mowers.
If you use a starting fluid, just use 1 quick spray on the filter, or, rumour has it, you could blow up the engine/crack your crankcase. Many canned spray starters are lubricated now and marked for 2 cycle and lawn equipment use.