Might take a 5 gal. drum to corral the worms now...
We posted Nessim's inquiry re: if oil analysis was done on the bike(s) from which failed plates were removed. No direct yes / no response or hard data as of today. It just re-animated a necro thread with more anecdotal responses..
Pics of failed clutch plates notwithstanding, our main takeaway is this;
Shell has changed formulas on some Rotella oils, enough to remove the API gasoline engine rating from the API donut altogether. Our guess is some time between 2020 and now, based on info from API. We see here that the latest API gasoline rating is SP.
www.api.org/products-and-services/engine...egories#tab-gasoline
Gasoline engine (S'x') is the rating in the API donut label, where 'x' is the incremental rating. We still have a few old quarts of 10w-40 from cases of Castrol SJ-rated oil on the shelf we've used for break-in of rebuilds.
API rating SM is the latest one that appears in the API donut on all but one of our Rotells 15w-40 dino oil containers. API SM also appears in the API donut of the almost-empty gallon of Rotella 5w-40 synthetic that produced undesirable tranny & clutch feel in our ST-1300A..
The Rotella 15w-40 dino that we bought in early 2023 is missing any gasoline (Sx) rating at all, showing only diesel (C'x'-4) in the API donut, where 'x' is the incremental diesel rating. Latest API diesel rating is CK-4, although earlier (Cx-4) diesel ratings are also still current.
www.api.org/products-and-services/engine...-diesel-c-categories
What does it all mean for us, wet clutches & vintage bikes? Dunno.
The single gallon of Rotells 15w-40 dino that's missing the API gasoline gasoline engine rating altogether will go in our highest mileage cage. We'll consume the rest old oils we have on the shelf that haven't caused us any problems in bikes & the cage. Once gone, we'll be looking for the JASO certification shield & cert # on our bike oils.
We pays our money & we takes our chances.
Good Ridin'
slmjim & Z1BEBE