Lets talk a little about viscosity. As everyone can agree that we as a group cannot agree on which motor oil to use. As ststed in my owners manual if I don't use Yamalube I can use any SAE 10W30 motor oil without friction additives. So I take that to mean Yamaha does recommend car or automotive motor oil. So now that brings me to this question. If Yamaha recommends SAE 10W30 what happens if I put 5W40 or 15W40 or even 20W50 in it? Yamaha doesn't recommend 5W40 but 10W30 is within the range of 5W40 so is it alright? Isn't 5W40 a little to then on hot days and a little to thick on cold days? I don't remember reading anything about what climate you live in so I assume Yamaha took that into consideration when they recommend any SAE 10W30 oil? Let the fun begin and hopefully we will all learn something from this.
Harry:puzzled: