CAUTION WHEN CHOOSING OIL

[Gumby 1100_imp]

Yes!!! If you run, for example, Mobil 1 10w40 synthetic in your bike and you need to top up, your first choice should be the exact same thing. If its not available, get Mobil 1 20w50 synthetic. If you can't find that, get a non-synthetic of the same brand/weight. Once you've exhausted all the oils of the same brand, then go to another brand and change ASAP. Mixing weights isn't a big deal to get you home because they will mix and 'average'.

Mixing brands is bad because different companies use different additives and you can't know how they are going to react. Most of the time, its probably okay. But its not worth risking any negative chemical reaction once all the additives and detergents get warm and begin breaking down as they are designed to do.

This is based off what I found on the bobistheoilguy forum those folks are crazy knowledgeable.

I understand your arguments, and agree that it would probably be best not to mix brands or types purely on the basis of chemical compatibility.

However, has anyone ever seen a single piece of documentation that shows any adverse affects from mixing brands or mixing synthetic with dino oil?

As long as you change your oil and filter regularly and stay within the engine manufacturer's specified rating and viscosity, I think that the worst thing anyone has to worry about is winding up with a strange shade of oil, like when you mix Royal Purple with Golden Spectro