I drive an FA50 (Suzuki, 1984) and the manual suggest using 20W40 motor oil in my transmission. Unfortunately, this oil is unavailable in my area.
I know 10W30 and 15W40 would both do fine, but I would like to know which would be BEST (second ofcourse to the 20W40 I can not find)?
What do the numbers mean, I know it has to do with weight and the usual temperature of the environment in which I ride... but that's about it. So, could you send me a link that explains this or do me the favor of explaining this in a way that I could choose which oil is best suited for my moped.
Thank you for your time and enjoy the summer; a lot of riding hours are waiting.