I am telling you that you don't know what cold is! Us folks up north are freezing our asses off!!! Below zero temps, snow and just downright miserable.
Are you trying to gas it before you start it up? Kind of like we used to do on the old bikes? That could be an issue. I would still check out all I have already said. Sometimes what seem like little things get overlooked. You don't have to be an electrician to check connections. Just check to see that all the connectors are pushed all the way in and bolts and nuts are tight. Make sure the battery has a full charge. Have I not stressed this enough? MAKE SURE THE BATTERY IS AT FULL CHARGE. I am not trying to seem angry with you; 99% of the time, it is these simple things that cause these issues.
Worse comes to worse; Spray some quick start in the carbs. If it fires and runs until it evaporates, it is a fuel system issue.
Steve