04-06-14, 09:15 PM
I'm using 10w50 full synthetic with JASO specification for 10 years without any problems.
My personal guess is that you will hardly notice any difference whatever oil you use within the usual lifetime and use of your engine. Even if some bearings suffer you will not recognize it unless you disassemble the engine and inspect the details. If used "normal". The picture might be different under extreme conditions, temperature or race.
The difficulty is to distinguish between bad and good oils. The other day I found a writing from a guy who obviously did some decent backgound research. Maybe worth to read:
http://motorcycleinfo.calsci.com/Oils1.html
Anyway you should also be fine by sticking to the original recommendation from Yamaha.
My personal guess is that you will hardly notice any difference whatever oil you use within the usual lifetime and use of your engine. Even if some bearings suffer you will not recognize it unless you disassemble the engine and inspect the details. If used "normal". The picture might be different under extreme conditions, temperature or race.
The difficulty is to distinguish between bad and good oils. The other day I found a writing from a guy who obviously did some decent backgound research. Maybe worth to read:
http://motorcycleinfo.calsci.com/Oils1.html
Anyway you should also be fine by sticking to the original recommendation from Yamaha.