CleanSump
Site Donor 2026
I want to believe, therefore it is. "All" is a very finite word.
20W-50 to 10W-40? Is it safe?
- Thread starter Phatboyaa.131
- Start date
Moly, zinc and boron have no negative press, per se, with respect to a wet clutch to my knowledge unless there's something I missed on this forum. Based on my experience there are no issues, not just floating out food for thought.
Manufacturers would not put elements in their oil above and beyond what is considered traditional amounts in order to become energy conserving, if the oil is disqualified from energy and conserving from the get-go because of viscosity. That's a business fact. Zinc is lower, moly and boron are higher and were not present at all when friction modifying came to be a buzzword, decades ago in the proportions they are now. Friction modifying is a bunch of bull crap yet provides very good discussion despite never having been identified. I would venture to guess the only thing friction modifying is the actual viscosity. There's no part of the additive package that contributes to that unless someone can show otherwise.
Manufacturers would not put elements in their oil above and beyond what is considered traditional amounts in order to become energy conserving, if the oil is disqualified from energy and conserving from the get-go because of viscosity. That's a business fact. Zinc is lower, moly and boron are higher and were not present at all when friction modifying came to be a buzzword, decades ago in the proportions they are now. Friction modifying is a bunch of bull crap yet provides very good discussion despite never having been identified. I would venture to guess the only thing friction modifying is the actual viscosity. There's no part of the additive package that contributes to that unless someone can show otherwise.
It's the lack of or a reduced level of certain friction modifiers that makes the JASO rated oils meet the SAE #2 clutch test friction specifications defined in JASO T903. What else in an oil's formulation would affect the friction level to meet the JASO friction specs if it's not connected to friction modifiers? Sidenote - ATFs also need to meet a defined oil friction level to work properly in an automatic transmission, another type of wet clutch.
Oils above xW-30 aren't formulated to be "Energy Conserving", but that doesn't mean they are void of friction modifiers. There's more to friction than just the actual shearing of the oil film as a function of the oil viscosity. There are AF/AW additives to help reduce wear for parts in the boundry and mixed lubrication regimes. Even with a xW-40 or xW-50 there are parts rubbing together that AF/AW additives help to reduce friction and wear.
If the type and level of friction modifiers didn't matter, then every oil on the market would meet JASO (and JASO probably wouldn't even exist in the firstplace), and all the motor oil manufacturers would put that it "Meets JASO MA/MA1/MA2" on the oil bottles to sell more oil. Will a non-JASO rated oil work? Sure it can, and a lot of that has to do with the specific design and clamping force of each specific clutch (number and size of plates and the pressure plate/springs clamping force) which means there could be a lot of performance variation. Doesn't mean any oil will always perform well in a wet clutch. A weak or badly designed clutch will obviously be more sensitive to the oil's friction level.
Last edited:
It's been 13 months since OP's registered presence was last seen here but for other readers who may be interested, Shell sells its Advance 15W-50 Fully Synthetic 4T for motorcycles in Asia. JASO MA2 certified too.
Zinc moly, boron are typical friction reducers/modifiers. Oils above 10W-30 or oils below 10w30 all have them. Agree.
Recent UOA of Pennzoil Ultra Platinum 5w20 has 70 ppm moly, 88 boron and 659 zinc. Most definitely an energy conserving oil and NOT JASO. Castrol 5w30 Edge with 58 moly, boron 11, zinc 842. Same as above, energy conserving yet not JASO. Kirkland 0w20 72 moly, 0 boron, 795 zinc. Energy Conserving, not JASO. Honda 0w20 65 ppm moly, 52 ppm boron, 906 ppm zinc. Energy conserving, not JASO.
Bel-Ray 20w50 semi-syn has 153 ppm moly, 34 boron and 894 zinc. Eliminated by viscosity alone from energy conserving, yet JASO MA2 rating. Honda HPS 10w30, 89 ppm moly, 49 ppm boron and 1008 zinc. Meets JASO MA2. Redline 20w50 from my analysis 290 ppm moly, 45 boron and 1672 zinc, JASO MA2. Amsoil 20w50 ftom my analysis 108 moly, boron 124, zinc 1209. JASO MA2. Valvilone 20w50 syn, 24 ppm moly, 272 ppm boron, 1070 ppm zinc. Amsoil 10w40 metric moly 68, 195 boron, zinc 1224. Not energy conserving yet JASO MA2.
That cross section of analysis can done over and over with multiple oils that are energy conserving versus JASO approved. Energy Conserving is not moly, boron or zinc dependant by themselves or in combo. The thing I see is viscosity may be a common thread that can connect this, or other difference that has not been defined as a specific additive.
Like said earlier, if all oils above xW-30 could meet the JASO friction spec requirements then all an oil company would need to do is have the friction specs tested and then put "Meets JASO MA/MA1/MA2" on the bottle or jug. They wouldn't even have to send the test data proof and register it formally with JASO (that's what Shell does with Rotella), which isn't that hard to do once the testing has been done. So the formulation has to matter in terms of oil friction performance. The final formulation is probably a more comple synergy between all the additives, and the base oil could also be a factor. There have certainly been some wet clutch bikes that don't like non-JASO rated oil. Each bike is its own "test bed" when using non-JASO rated oil - most may seem to work fine , but not ever bike will.
Honda has both auto xW-30 motor oils (not JASO rated) and xW-30 motorcycle JASO rated oils. What's the formulation difference?
I may have misunderstood when you said they are mainly disqualified by viscosity alone. That means in the majority of circumstances. What circumstances are they disqualified by viscosity alone yet energy conserving? None that i can see based on what you shared. The difference in additives in my previous post is pretty consistent that there is no consistency with respect to additives being the cause of energy conserving or not. As you said, most oils above 10w30 are disqualified regardless because of the viscosity lowering efficiency and no amount of friction modifiers can overcome the disqualifying by viscosity spec. A manufacturer would be folly to disqualify an oil by the viscosity offering alone and try to make up with friction modifiers. And it's clear the differences are minor and not statistically relevant to wet clutch compatibility versus not. They would be throwing money after foolishness to overcome viscosity with additives. Like I said, maybe I have read that wrong?
Last edited:
Yes, from what digging into it any viscosity above a xW-30 is automatically disqualified from getting the API "Energy Conserving" approval. The HTHS viscosity which affects fuel economy is too high for construction, regardless if the formulation has enough friction modifiers to make it perform like a xW-30 with respect to fuel economy.
I appreciate the good dialogue, I'm thinking the jury is out with all of this in my opinion. Or the jury is doing just fine and the additives or lack thereof are a whole lot to do about nothing.
I was editing my post as you were posting so I put some more thoughts after you had quoted. However, I appreciate the dialogue like I said. This is good discussion in my opinion.
I was editing my post as you were posting so I put some more thoughts after you had quoted. However, I appreciate the dialogue like I said. This is good discussion in my opinion.
The way I look at it is JASO wouldn't ever have materialize if automotive motor oil's friction level at some point didn't matter to motorcyle wet clutch operation. I'm not going to use my bikes as a wet clutch test bed, that testing has already been done by people using the SAE #2 friction test procedure specifications in order to lable their oil as meeting the JASO friction specs. The formulation also has to meet some other requirements too, but the 3 different types of friction specs in JASO T903 are the main focus. Yep, good dialogue.
Last edited:
The litmus test would be was there an increase in clutch slippage that lead to JASO being introduced in 1998 after the energy conserving label in 1997?
JASO was a quick turn and burn so to speak, as it happened within the year after energy conserving was added to the back of oil bottles. I don't read about "the year energy conserving oils killed the motorcycle clutch", per se. I can't find a rash of clutch slippage at that point in time when I search for it.
Seems a lot like the "wizard behind the curtain" and a solution in search of a problem that was marketed as the sky falling and has been with the oil world ever since.
Like I've said, friction modifiers have not been identified other than the traditional ones that are discussed day in and day out. The examples I compared a few posts back are no different in quantities between energy conserving and JASO oils. Only difference for practical purposes is the oil grade.
I choose to use motorcycle oils from the fact they hold up very well in a shared sump such as Mobil 1 4T 10w40, 20w50 VTwin, etc.
JASO was a quick turn and burn so to speak, as it happened within the year after energy conserving was added to the back of oil bottles. I don't read about "the year energy conserving oils killed the motorcycle clutch", per se. I can't find a rash of clutch slippage at that point in time when I search for it.
Seems a lot like the "wizard behind the curtain" and a solution in search of a problem that was marketed as the sky falling and has been with the oil world ever since.
Like I've said, friction modifiers have not been identified other than the traditional ones that are discussed day in and day out. The examples I compared a few posts back are no different in quantities between energy conserving and JASO oils. Only difference for practical purposes is the oil grade.
I choose to use motorcycle oils from the fact they hold up very well in a shared sump such as Mobil 1 4T 10w40, 20w50 VTwin, etc.
Oil formulators were working on making motor oils "Energy Conserving" way before JASO came along in 1998. And the actual "star burst" logo was put on oil bottles many years before JASO ever came along. I don't think JASO waas some "wizard behind the curtain" trying to scam the oil industry and motorcycle owners in some way, there was a legitimate reason it was formed based on how motorcyles with a wet clutch were responding to automotive motor oils in the 1990s Like said, if every oil would work great in a wet clutch, then any oil maker could slap on "Meets JASO MA/MA1/MA2" on the bottle and call it a day. Or if someone uses their bike as an SAE #2 oil friction "test bed", then they could write "Meets JASO MA/MA1/MA2" on the bottle with a Sharpie pen if the clutch didn't seem to slip.
Thing is, a wet clutch could slip slightly and be hard to detect. What's that going to do in the long term for the clutch plates? ... might result in some fiber plate glazing since that's caused by slippage and some more wear over time.Source of below quote:
https://www.motor.com/magazine-summary/mastering-basics-fluid-selection-november-2003
"Since 1993, oil quality also is identified by the API “starburst” symbol. To earn the starburst, oils must meet the energy-conserving II requirements of the International Lubricant Standardization & Approval Committee (ILSAC) and be certified as the correct oil for gasoline engines in cars and light trucks. Therefore, only multiviscosity oils qualify. Oils that qualify for the starburst symbol also may carry ILSAC classifications GF-1, GF-2 or GF-3, which indicate the energy-conserving qualities."
Here's some more info - go to the "Recent Service Classifications & Viscosity Requirements" section:
https://www.motor.com/magazine-summary/mastering-basics-lube-basics-november-2002
Note - there is also a PDF download at the bottom of those links.
Last edited:
what oil?
unless you see cold engine start temps below the 50s , 20w50 gives excellent wear, better than 10w40.
by the way cold start wear with 20w50 does not really exist, cause the oil never really drains off the parts, like thin stuff. so yeah you might have a slower pressure build, but the parts are covered with oil, so really a non issue.
I have high performance mc motors, running 20w50 with no cylinder wear pushing 100,000 miles. I do have to replace light weigh pistons, not from wear but metal fatique risk, the wear rate is excellent and low.
but you can run 10w40, its not going to be a big differnce, but again with a decent oil Brand.