but as some have suggested letting it sitting around, especially in the cold weather causes the rattles,
I'd need to hear a more detailed explanation before I could accept that.
Reasons to not start during storage:
Lubrication
Oil has drained off the parts, some parts might take longer to get oil flow than others (CCT is a good example of that).
Cold oil is thicker than hot oil and doesn't flow as readily. I know they design oil to flow optimally both for cold starts and hot running conditions but show me oil that is not much more viscous when it's 12° F outside.
Condensation
Definitely causes water in exhaust and crankcase, probably spark plugs and throughout the engine, possibly even fuel tank. You won't get that out unless you ride the bike until it gets very well warmed up. Kaw says not to let the bike idle for prolonged periods. I ran mine 20 minutes one winter and steam still came out of the pipe when I shut it down.
Cold
Engine cranks over more times = more revs without lubrication (see Lubrication).
Excessive discharge from battery.
Stress on water pump if you have any slush in your antifreeze.
Backfires from fuel buildup caused by engine turning excessively before it starts.
When new, the bike sits in a crate without starting for months. There is nothing bad about not running a bike until someone buys it.
I don't start mine unless I need to for engine work and then I wait for a warmer day. I have used a heating pad on the oil pan when it was necessary to start when the weather was cold (look for a cheap one without auto-shut off). If you have a heated garage, I can't see a problem but I still don't see any benefit to it except you get to hear your engine run.
* Last updated by: Rook on 12/23/2017 @ 4:40 PM *
'08 MIDNIGHT SAPPHIRE BLUE Now Deceased