Recent diesel oil formulas MAY be causing wet clutch problems

We were very reluctant to post this, knowing how oil threads usually devolve into... whatever it is they devolve into.   Y'all know what we mean.

This is simply meant to be a PSA for those of us who use diesel oil in bikes because of their purported JASO MA rating.  We'd feel like we were doing a disservice to the  KZR community if we didn't share.

We were made aware of a possibly developing issue with wet clutches when using the most recent formulations of diesel oil that had performed well with wet clutches in earlier formula iterations.  This had slipped under our radar until a Rider on another forum linked to it on the st-owners.com forum. 

Many ST1100 / ST1300 Riders cover serious miles every year, akin to Gold Wing Riders. It's not unusual to see ST1300's with over 100K miles on them.  Oil threads are an ongoing 'thing' at the st-owners forum.

We, personally, have not had any problems using Rotella 15w-40 dino oil in our ST1300A, or one of our '74 Z1's.  But, we bought the 15w-40 gallons we have on the shelf a few years ago on Black Friday sales, and the formulas & API ratings have changed since then.  We only used the full synthetic 5w-40 once in our ST1300A, because slmjim didn't like the way the clutch & tranny felt.

The short version:
Motor oil producers modify formulas routinely to account for changes in motor design & materials and, changes in emissions laws.  There's chatter that some recent formulations of Shell Rotella 5w-40 full synthetic in particular may be causing wet clutches to fail in ST1300's.  The linked threads are the sum total of what we've read so far.  Conflicting info, some facts, & many opinions to wade through.  Draw your own conclusions:
www.st-owners.com/forums/threads/new-tre...-diesel-oils.184954/

www.st-owners.com/forums/threads/shell-t...e-rotella-t6.184924/

www.st-owners.com/forums/threads/rotella-t6.183960/

We've not researched beyond what is contained in the linked threads above 'cause we value our time & sanity.  We'll just offer our opinions:
Oil is literally the lifeblood of an ICE.  Once our stock of old-formula dino15w-40 Rotella diesel oil is used, we'll bite the bullet & only use motorcycle-specific dino (in Z1's) and full syn (in our CB750 Nighthawks & ST1300A) oils that have the JASO MA symbol & JASO certificate number on the label.

Good Ridin'
slmjim & Z1BEBE

I just put Rotella 15W-40 in my 750.  The bottle says MA/MA2.  What me worry?  

I just read two long threads on Bob Is The Oil Guy about Rotella.  One thing that came across is that in order to be certified as JASO MA/MA 2, the oil must also meet one of the current API oil specs.  Thing is, though, API is for gasoline engines.  Rotella and similar oils are diesel engine oils, thus they cannot be certified.  Shell tests Rotella to meet the elements of MA/MA 2, though, as related to wet clutch performance.  It's right there on the bottle.  It's also in the .pdf for the various Rotella oils.  I don't think there is anything to be worried about...

T6 yes, I think you may be correct. I have been using T4 with no issues.

The T6 mix meets the MA/MA2 requirements also.

If the label says it meets the JASO standard it should be good.

One takeaway from the threads that was not at all well presented is that suppliers can claim, in text, on the label that the product 'meets' JASO specs without being tested & certified by JASO.  That testing costs money that the suppliers may not want to spend.

JASO certification is indicated by the JASO shield & certificate # on the label of oil that has been certified.  Oil that is claimed to meet JASO spec simply has that claim appear in text sans JASO shield & cert. #.

www.jalos.or.jp/onfile/e-ok.htm

lubricants.repsol.com/en/news/como-saber...a-norma-jaso-repsol/

Certified vs claimed.  We pay our money & we take our chances.

Good Ridin'
slmjim & Z1BEBE

 

I'm repeating myself, but true diesel oils cannot be certified JASO MA/MA2.  They can be tested to meet the pertinent requirements, though, which is what Shell seems to be doing with Rotella.  To me, that's good enough.  If you can't live without the full cert, you best buy true motorcycle oil.  

Here is the list of fully certified oils.  Note: Look for MA and MA2 if you are worried about your wet clutch.  Oils certified MB are NOT for wet clutch bikes.

www.jalos.or.jp/onfile/pdf/4T_EV_LIST.pdf

Gotta love an "oil thread" 

Wookie58 wrote:

Gotta love an "oil thread" 

I LOVE oil threads!  

I've been on BITOG for years, but recently, I've been frequenting more often.  Those guys are the closest thing you will find to science over opinion, but there are still a LOT of opinions that affect postings.

One of the more opinionated topics is whether 0W-20 car oil is preferable over 5W-30.  I love those topics!  

Motorcycle oil threads are far more calm.  There is a long one over Rotella T6, though.  slmjim & Z1BEBE would love that one!  I've read a fair number of different oil analysis threads on Rotella, and I can't see anything in the current formula that would hurt a clutch.  If anything, there was more moly before, and that can hurt the clutch (if there is too much).  

Nessism wrote:

Wookie58 wrote:

Gotta love an "oil thread" 

I LOVE oil threads!  

I've been on BITOG for years, but recently, I've been frequenting more often.  Those guys are the closest thing you will find to science over opinion, but there are still a LOT of opinions that affect postings.

One of the more opinionated topics is whether 0W-20 car oil is preferable over 5W-30.  I love those topics!  

Motorcycle oil threads are far more calm.  There is a long one over Rotella T6, though.  slmjim & Z1BEBE would love that one!  I've read a fair number of different oil analysis threads on Rotella, and I can't see anything in the current formula that would hurt a clutch.  If anything, there was more moly before, and that can hurt the clutch (if there is too much).  

 

Beat us to it on the JASO list link.

We won't use Rotella T6 5w-40 in a bike again.  Clutch & tranny feel grew noticeably worse over the course of 3,000 miles in our ST1300A.  Changed it early because of that, before we were even aware of the issues documented elsewhere developing.  We've had zero problems with Rotells 15w-40 dino.

It was the pic of the ST1300 wet clutch plates that trusted forum user & ST1300 guru 'IGOFAR' posted in the third(?) linked thread in the OP that gave us pause, and the only reason we started this thread.



We pays our money & we takes our chances...

Good Ridin'
slmjim & Z1BEBE

That clutch plate looks to be disintegrating.  Not the common glazing problem that occurs with clutch plates when friction modifiers in an oil damage the friction material.

Did the guy on the forum collect an oil sample and send it in to Blackstone for analysis?  I certainly hope so.  Without science behind the investigation, all we have is supposition and opinions.

 

Nessism wrote:

Did the guy on the forum collect an oil sample and send it in to Blackstone for analysis? 
 

Will ask.

Good Ridin'
slmjim & Z1BEBE