Motul is the way to go. Ive used mobil one and wasnt too thrilled with it but once i tried motul I havent looked back. Been only using it since then in my last few bikes.
Not to disagree with you because you seem to be very intelligent but I will.....
I've found in all my bikes that each and every one likes a diff flavor.
In Blanca I've always used 10w-40 but from a few diff makers.
Same viscosity from diff makers and I could def tell a diff in how she felt, idled, shifted and rode. I use the Castrol semi synthetic 10w-40 in cool times and same stuff in 20w-50 during hot summer times. Both Blanca and my 97 Zx11 seem to prefer this stuff. Tried Repsol, too clackety clack and noisy was the engine. Tried Motul with same result. The Castrol she idles nice and quiet with hardly any valve train or engine noise. So again I hate to disagree with you but I def think you can tell a diff between diff makes of oil.
I use Perrier and change it out every 100 miles!
i run amsoil becouse im a dealer so i get it at cost
Any idea why Amsoil increases viscosity over mileage and time, as shown in a number of analyses?
In most UOA's after 6,000 miles the results are excellent and show no shear. After that the oil starts thickening. Analysis after 300 miles show a lot of shear (Thinner oil)
This is what concerns me, it appears as if they balance the additive package to deteriorate at about the time an oil change is necessary, to get the viscosity back into specification.
The next thing that concerns me is the fact that they will not factually state their base. So do we know is it mineral III, POA IV, or Ester V???
At least if you buy Silkolene, amongst a few others, you know exactly what you are getting.
For what it's worth: My Busa from Day one (Which was only a few months ago) would make a decent amount of upper engine clacking, which I attributed to valve/cam lubrication when cold, after warming up it would quiet down. I brought it in for its 600 mile service and even then it made the noise. I just figured it was normal. This past weekend I changed the oil again (i'm crazy yes, it only had 500 miles on it since the last oil change, but something was telling me to do it). I bought Mobil 1, 4T 10-40 and a K&N filter. Beleive it or not, the cold start upper engine noise is completely gone and the bike purrs at all operating temps.
Back to Mobil 1. Tried it on the third oil change because I'd read a lot of reviews saying it was sooo great. Made the already hard shifting bike shift even worse, to the point of being afraid of hurting something from all the missed shifts and false neutrals. Drained it at 1000 miles and went with the Motul, instant fix.