After reading your post I PM'd a trusted member of BITOG who is a tribologist.

I asked him, if he owned a Suzuki Savage 650 S40, which flavor of Rotella would he use in the bike .... T4, T5 or T6.

His response was: "I think I would use the SHELL ROTELLA® T6 FULL SYNTHETIC HEAVY DUTY ENGINE OIL as it has synthetic bases and extra cleaners to keep the rings from coking up."

Hope this helps.  

piedmontbuckeye wrote on 01/01/17 at 08:06:18:


http://www.thefreedictionary.com/tribologist
There is no "perfect" motor oil. It is, like most things in life, the best "compromise" of ingredients to meet a certain goal or situation.

Pick what is the most important attributes you require and blend the oil accordingly
http://www.oilspecifications.org/articles/api-sn.php

To improve one area you will have to sacrifice in another.


Like my tire engineer friend says about tires:
1)Long wearing
2)Good traction
3)Low cost
pick any two you want, I can't give you all three