Originally Posted by Bonz
The common element I see as well is thickening in non-shared sump big V twins. Yes, look forward to the UOA next year on the M1 20w50 V Twin in my 4 cyl ZRX1200 with a shared sump.
Interesting that Valvoline 20w50 Syn MC oil thickened as well in these links, but HD Syn3 20w50 did not go out of limits.
https://www.bobistheoilguy.com/foru...alv-syn-20-50-motorcycle-oil#Post4640080
https://www.bobistheoilguy.com/foru...mited-103-c-i-blackstone-lab#Post4612695
In this link, M1 15w50 did not go over grade, but barely under the upper limit in a non shared sump (as defined by Blackstone) but the same oil in my analysis at the start of this thread (farthest column to the right) did go down a lot.
https://www.bobistheoilguy.com/foru...-hd-107-has-high-copper-wear#Post4458113
Once again, different "Values should be" from Blackstone for a "50" wt, but the relative comparison is valid, IMO.
Nice catch on the Valvoline thickening too. I am a fan of Valvoline Motorcycle oils and if my bike required a motorcycle oil it would be my go to oil.
The M1 15/50 being an API rated automotive oil (and an obsolete CF diesel rating might still be listed on the bottle) might explain it not thickening but is still out of spec for Harley as well as M1, Amsoil, Red Line motorcycle oils are out of spec for Harley.
With all the above said, most do not know, including the people using the oil (Mobile1 Amsoil, Valvoline, Red Line motorcycle oils) in those links is, none of those oils are in spec as to what Harley Davidson requires in their touring bikes (possibly all the others too).
The HD oil also may explain it not thickening due to it being formulated more like an HDEO.
HD requires you use their oil or HDEO diesel rated oil of CH4+ or higher (if their oil not available) they go one to state switch back to HD oil once available but whatever.
Whether it matters who knows.
I do use a 15/50 HDEO in my Road King, no thickening.
Amsoil does make a HDEO diesel oil in the 20/50 weight that would meet Harley specs but for some reason no one uses it, they go for the motorcycle specific oil that doesnt meet the spec.
Amsoil lists it as 20/50diesel oil and mentions also for motorcycles I assume because they know Harley requires a diesel oil but every UOA I see the owners use the standard non diesel motorcycle oil.
I honestly believe these motorcycle oils are formulated to thicken up in order to hold viscosity and shift quality in shared sump bikes and not formulated for non shared bikes such as Harley.
They do not meet Harley specs of a HDEO Diesel oil.