It's actually best not to periodically start it up while in storage. Consider if you will how long it really takes to get the engine and the motor oil completely and evenly up to full operating temperature even with a load on the engine riding the bike (around 10 miles on average). Just letting the bike sit in a garage idling with no load isn't going to do the trick, but it could cause localized overheating of parts due to the lack of air flow. Most folks who "fire her up" on a regular basis during storage actually do more harm than good.
If you want to crank the bike over to distribute some oil, pull the spark plugs and then leave the ignition OFF and crank the engine by energizing the starter solenoid directly with a jumper from the starter hot wire. No fuel, no spark, no combustion, therefore no combustion byproducts or moisture introduced to the engine or oil. Shoot a little fogging oil in the plug holes to lube the pistons and cylinder walls while cranking, then when finished reinstall the plugs.
Jerry.