Wintertime in most states means the motorcycle is parked until spring. While those who can still ride might consider that absolute downtime, it's really not in the short-term or all winter long-term. Winter might mean storage of the motorcycle but doing in properly can keep the rider rather busy for awhile. Sure, riding is more fun, but proper storage is imperative for a problem free future riding season.
Winter storage preparation: if stored properly at the beginning of winter, a motorcycle will be ready to roll come the first moderately warm day in the spring (or even late winter). Improperly stored, it'll be a headache and an added avoidable expense.
DO: purchase a battery maintenance charger if one isn't already on the shelf in the garage. Batteries are expensive, more nowadays than ever. Proper maintenance of a nominal charge extends battery life, period. Ensure proper connections on the battery to the charging pigtail while prepping the machine. Loose battery terminals will increase resistance and reduce the efficiency of the charger. It may even damage it in the long-term.
DO: top off the fuel tank and add a fuel stabilizer. A full tank reduces the amount of water brought about by condensation inside the tank. This also exposes the inside of the tank to air. If the designed space inside the tank is exposed to air for an extended period, normal moisture from condensation and the fuel itself can cause the tank innards to rust. A fuel stabilizer helps prevent the fuel from going bad overall and helps prevent issues with the ethanol in gasoline. If non-ethanol gasoline is available, fill the tank with that product and run the engine for awhile but not in an enclosed space, of course. The motor needs to be warmed up a bit for the next part anyway.
DO: change the oil and filter. Oil that's been run on say for even one-half of it's normal life has started to change chemically. Sitting still in a crankcase causes further change. Oil tends to be come more acidic over time. Old oil can also have some water mixed in after sitting for awhile due to that condensation thing again. Put new oil and filter on now and be ready in the spring to ride.
DO: clean the bike thoroughly. Some wax won't hurt either. Dirt harbors chemicals that harms painted and chromed surfaces. Organic matter like bird poo and insect carcasses likewise does the nasty on shiny stuff. Get rid of it. Plus, throwing a cover on a bike that is dirty can grind the dirt into paint, causing scratches.
DO: top off tire pressures before storage and check periodically during the storage period. This is mainly for tire life but a properly inflated tire is easier to roll. And no doubt a stored bike might have to be moved from time to time in order to access something in the garage or basement. Avoid frustration by keeping the tires juiced.
DO: drain the float bowls of fuel if the bike is carbureted. If equipped, make sure the fuel shutoff is off and locate the drain screw(s). Do this in a well ventilated area, free of any sparks or flame. Definitely not something that's done after the bike is rolled into the basement near the furnace. Leave the drain screws open. This will allow any residue to evaporate. No fuel in the carbs means no possibility of fuel spoiling and blocking the small jet passages. Invariably, fuel left in the carbs will mandate pulling them apart for cleaning. Put a note on the machine as a reminder to close the drain screws in the spring. A good place is right on the key ring or on the speedo display nacelle.
DO: if the bike is liquid-cooled, check the coolant with a hygrometer especially if where the bike is stored will get below freezing. Watered down coolant can freeze, causing a ton of expensive damage.
DO: if covering the bike and the area is moist like a basement, make sure the cover breathes and check periodically for moisture buildup underneath.
DON'T: run the bike while stored for short periods. Running an internal combustion engine without getting up to full operating temperature can create excessive moisture in the engine and exhaust. With proper prep work, running the engine won't be necessary and can actually cause more problems than its worth.
Proper storage means some work, but it's sorta fun work. Why? It looks forward to springtime and another great season of riding.