This is not about what to wear for cold weather, but how to put it on. How you perform the act of getting dressed can mean all the difference between a cold ride and a warm ride, even if you are wearing exactly the same gear in the same weather. It seems to me that although there is a lot of information about what to wear, nobody ever seems to talk about how to put it on.
According to the Lost Motorcyclist (me), the basic principle is this: that you must not get sweaty and start perspiring while getting dressed for cold weather. That's because moisture cools you off, and conducts heat through otherwise warm insulation. That moisture will stay trapped in place under heavy winter gear, and you will get cold much sooner than if you started completely dry.
It's not as easy as you think to avoid getting sweaty under your cold weather gear. Most people get dressed in a warm house, at a temperature much too high for their warm clothes. And some cold weather gear is difficult to get into, meaning it takes time and physical effort, both of which increase the perspiration and moisture inside your clothes.
The first, most basic thing is to not begin getting dressed immediately after a physical workout. Wait for your body to cool down first. And make sure all your normal clothing, that you will be wearing under the winter gear, is dry before you start.
Second thing is to take care of all preliminary tasks before you put on your cold gear. In my case, that would be taking the motorcycle out of the garage and getting it pointed in the right direction for a ride. I do that before I put on any cold weather gear.
Third is to actually put on most of the gear - probably overpants, boots, and sweaters. This must be done quickly and effortlessly. If your gear takes too much time and effort to put on, you should get better gear or practice your technique.
Fourth, put on the last of the cold weather clothing outdoors, where it is cold. That would probably be the helmet, outer jacket, neck warmer, and gloves. I also usually leave those items inside the warm house until I am ready to go.
If you have done it all right you can be on your motorcycle, heading out of the driveway feeling warm but not overheated, and you can ride for a long time before you start to feel cold. The actual time might range from half an hour to all day long.
How far you can go before getting cold is a combination of many things: the temperature outside, the type of gear you are wearing, the wind protection on your motorcycle, your own body's tolerance for cold, and your heating system (if you have one like electric or chemical heat sources.) But among of all of those factors, the most poorly understood, yet critical, is the art of actually getting all that gear on and getting out the driveway.
Here is a funny video from Columbia sportswear that illustrates one way to put on cold weather gear, and there is some truth to it.