Recent diesel oil formulas MAY be causing wet clutch problems

I know Kevin Cameron. I have for 30 years. When we talk about oil, he dismisses all the shit on the side of the can and talks about oil molecules "see, they added a molecule ..." .

I know him, love him as a friend but I only comprehend like maybe a third of what he says.

Anyway I'll ask him what he thinks about this if anybody wants to know.

Kevin Cameron is one of our favorite motosport writers.  Learned much in the nuanced technical arena from him over the years.  Speaking for ourselves, of course we'd like to have his take on this.  Looking forward to it.

Good Ridin'
slmjim & Z1BEBE

slmjim+Z1BEBE wrote:

 

I just read that linked thread, and this is what is said about this photo... "This is a typical example of what using the wrong type/weight of oil does to your clutch plates."

In other words, this is not a photo of a clutch damaged by Rotella T6.  Honestly, and no disrespect to slmjim+Z1BEBE, but I call BS on this persons claim.  The clutch friction material on that plate is denigrating.  This does NOT happen due to "wrong weight" or type of oil.  

I totally respect the observation that shifting performance deteriorated from using T6.  I wouldn't use it either, if this was my experience.  

 

If I saw that picture without any explanation, I would assume the clutch had been badly abused and was burnt to a crisp. 

If I didn't know better I would have said it had been run exceedingly low on oil or the motor had been cooked. The clutches we used to take out of Craig's stunt bikes didn't look like that after endless 5th gear burnouts etc !!!!!

I've heard several times that the Rotella T6 causes crunchy shifting after a bit but nobody ever claimed it destroys clutch frictions. The only way to make frictions look like that is some serious abuse.

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