It’s not just the bike's exterior components that’s of concern here.
The other issue is that starting the engine produces water vapor in ithe exhaust, a by-product of the combustion process. When you see water dripping out of your exhaust on a cold morning it’s because the water vapor is condensing on the still-cold exhaust pipes and mufflers. If you do not get the engine hot enough, and for long enough, this water will not evaporate away completely, causing corrosion.
Also, when you start a cold engine there’s blow-by of combustion gases and water vapor past the rings that ends up in the sump. This contaminates the lubrication oil, often giving the oil a brown foamy appearance. Over time, the engine heat drives off this water from the oil, but again, only if you ride long enough and the engine gets up to a high enough temperature. Of course, this is hard to do in winter without covering the radiator to block-off the air flow.
Since there’s really no benefit in operating the bike during the off-season (i.e. seals, wheel bearings and tires don’t need it) you often encounter advice to just let it sit till spring. But I say that if you get a nice warm winter’s day take it out and ride it. But ride it long enough to purge the moisture in the crankcase and exhaust. Block-off a part of the radiator air flow to get it up to summer-like coolant temperatures. Reconsider if the roads still have any salt residue on them. It gets into everything, corrosion - Big Time.
You've probably heard that certain parts like seals benefit from not drying out, meaning that you should periodically crank or start the engine so they will remain soaked in oil. This was once a problem for natural rubber parts, but no longer an issue with synthetic materials. Other parts like wheel bearings, tires and suspension seals really won't benefit from being operated during winter storage.
