Originally Posted by
I-Like-To-Bike
I think good advice is to use whatever motor oil is on hand, whatever the viscosity, and a good inexpensive source is the residue remaining in the packaging container of whatever oil is used when changing motor oil for any motorized vehicle.
I've experimented a lot and found that in the summer time, 0w30, even 5w40 are a bit too "thin". For cold winter, 20w60 (or gear oil) is too thick.