... the heater comment brings up another point: some people feel the need to start their bike up in the garage during winter storage to get things splashed around and fluids flowing. The owners manual for our bikes specify the temp range (over night cold soak temp) for the different oil ranges, and for both my bikes it says that 20W40 oil is only good down to 40F. If you want to be strict about it, that means dont start your engine if its 39F or below overnight with 20W40 oil in the engine. If you have a space heater and you really feel compelled to spin that crank when its 0F outside, warm the bike up first. And then remember that oil pressure coming off the oil pump is a function of RPM, rev it up a little to build the oil pressure, dont let it just sit there and idle when its cold.
There have been a few discussions about this, and there are many websites that try to spec what oils are good down to what temperatures, but motorcycle engines, esp air cooled engines, have much wider tolerances on the parts than car engines, or water cooled engines. The critical design issue is whether the oil pump can push cold (thick) oil all the way to the furthest bearings in the heads and transmission parts when you start it up in the cold. If the oil doesnt make it to that last bearing journal the shaft will be sitting there spinning metal on metal, doing a lot of damage.
Its better to let the bike hibernate on those cold winter days, than to try to keep waking it up, if you have a cold garage.
If its in your living room, just open the windows a bit :^)
Last edited by KCW; 12-15-2018 at 09:17 AM.