Join Date: Aug 2011
Location: Sack-a-Tomatoes, CA, US
As long as you engine gets up to its normal temp, it should still be a 40. For colder climes, you usually need a lower low number.
Go with Rotella T6 available at wally mart. It is a 5W - 40, so will work just dandy when it is cold out and still is a 40 when warmed up plus it is a full synthetic so will protect your engine better than petro-based oils.
Black Beast = '71 CB750
Lazarus = '86 VT1100C rescued from a salvage yard.