What kind of set up are you running? Im on a '14 yz450f with a MH ST, and have had nothing but issues starting in cold weather. One thing I found that makes a big difference is when hauling your bike in the truck, tarp the bike, or at least cover your engine. Another trick I learned is bring a large tarp or blanket, cover your bike, then run a hose from your truck exhaust underneath the tarp while you get suited up for the day! Also, make sure you are using the right oil for cold weather, I use Rotella T6 5w-40.