Those using Diesel oils

[Pete in PA]

Reports starting to come in of clutch slipping/damage to clutch plates with Shell Rotella and other diesel oils even with JASO ratings.

The latest change has CK4 but no API S rating as in SL, SM, SN etc.  I think we're at SP which is in itself questionable.

I put in Rotella T6 15-40 late last fall, rode a couple times, and stored for winter.  First ride of this season my clutch slipped. Chalked it up to just age of the plates and changed frictions, sanded metals and new springs. Put in the same Rotella again.

Then I found these posts.
https://www.st-owners.com/forums/threads/rotella-t6.183960/

https://www.st-owners.com/forums/threads/new-trend-in-diesel-oils.184954/

I drained brand new Rotella and put in SuperTech 10w40 Synthetic Motorcycle oil.  It's rated API SL JASO MA2

Just be warned, I think it's just beginning, this year will tell.