No doubt there is a good one liner in the phrase "snow in the hills" and Stiff Bubba,but I shall refrain and reply to your query.
The Berg manual suggests that you should clean your bike well and change the oil c/w paper filter and clean the small filter.
Next turn the fuel shut off to off and start and run you engine until it quits.Drain the fuel in the carb and also drain the fuel tank dry.
Remove the battery and charge it
Check antifreeze strength and top up as reg'd
Put a few cc of oil down the spark plug hole and turn the engine over a few times.Replace the plug.Place piston at TDC(both valves closed) Correct tire pressures and lube any pivot points
Store in a dry place not subject to temperature flucuations and cover with a breathable cover.....
Wait for spring...........nsman