I'm looking for a straight 30W oil (preferably synthetic) that can be used in a motorcycle transmission with a wet clutch. The engine is an early 80's Rotax two stroke and the manual calls for an engine oil of this type. I had this bike during the 80's in the UK and used 30W Castrolite in it but I would think there is something better than that out there now.
30W Oil Suitable For Wet Clutch
- Thread starter Robin127
- Start date
I use 30 in one of my bikes because that is what it was specced for...it's a 4 stroke and no problems. My last 2 stroke was a DT230, and I used a variety of oils in it - 10W-30 engine oil, ATF, and motorcycle specific gear oils. All of them worked just fine. I can't see a problem with straight 30 at all, most 2 strokes were recommended for 30.
Jaso rated for wet clutch and don't worry about straight 30w. Oils have come a long way since the '80's. Just like premix at 20:1 is long gone with 40:1 being standard.
I believe the modern standard recommendation is 50:1, not 40:1.
Is KTM still recommending 60:1?
All the manual says is SAE30 motor oil. As I said I used Castrolite when I had the bike in the '80's, I think it was SAE 10w-30w.
Yeah, SAE30 (technically not "30W") so as others have also said, you could use a good 10W-30 instead and be fine.
Use no oils labeled "Energy Conserving" in the starburst emblem, they will destroy a wet clutch. Most if not all lower viscosity oils (5w-30, 10w-30) will destroy. Use a single grade 30 as specified or a higher viscosity multi grade without the starburst emblem (virtually any oil 40 or above) like a 15w40 or 20w50 and you'll be safe.
Go get some Honda 10W-30 oil ... it meets JASO MA specs.
pathanmotors.com
Honda 4 Stroke Engine Oil JASO MA SAE 10W30 | Pathan Motors- Official Website
Product Name: Honda 4 Stroke Engine Oil JASO MA SAE 10W30 Grade: 10W30 Can: 1 Liter
pathanmotors.com
Amazon.com: Honda Pro GN4 Motor Oil - 10W30-1 Gallon/- : Automotive
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Rotella T1
Negative...
The holy trinity of science is 1)Reason 2)Observation 3)Experience...
employing those tools we observe that the primary cause clutch slip
are high mileage... mileage is the constant among all of the clutches
that begin to slip... oil choice whether JASO approved or not is not a
constant... High mileage is the constant where all clutches begin to
loose grip due to normal glazing and contaminates that build up over use..
JASO has approved 1,537 oils as of Dec 2019 which covers virtually
everything on the market including 0w oils that would qualify as
Energy Conserving... That is because Energy Conserving is not
additive... its an API mileage test that this "oil MAY result is an
overall saving of fuel in the vehicle fleet as a whole" there is
nothing in the oil to defeat a wet clutch...
JASO approve list examples...
234 0w30 Energy Release SN 4T Jaso MA
238 0w30 Energy Release SN 4T Jaso MA
242 0w40 Energy Release SN 4T Jaso MA
243 0w40 Energy Release SN 4T Jaso MA2
244 0w50 Energy Release SN 4T Jaso MA2
389 0w30 Honda Ultra G4 Jaso MA
387 0w30 Honda Ultra G4 Jaso MA
401 0w30 Pro Honda HP4 Jaso MA
My RC45 has over 57K miles and those are miles not in moderation
either... its a homologated race bike with a first gear good for
90mph... since 98 I've been running Mobil 1 Energy Conserving oil 365
days a year... with no clutch slippage due to oil...
My current favorite...
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Any one of 30 grade 100% synthetic motorcycle specific oils will meet
and exceed your mileage expectations...
My current favorite motorcycle oil...
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Some may suggest but Shear and Wear are to be address separately...
Wear
Mechanics and Engineers and Manufactures all agree 70 percent of
engine wear occurs at start-up, Consequently, choosing a shear stable
5W30 is the better choice and less start-up wear than a 10W30
whereas a 10W30 is a better choice than a 15W30 and so on...
Adequate oil supply happens but its not instantaneous when we hit
start unless you have a pre oiler accumulator... it takes critical
seconds for the oil to adequately flow during cold start up... cold
start up is defined as any temp lower than operating temp... this is
what the W test tells us... that cold 5W flows quicker than cold 10W
and that cold 10W flows quicker than cold 15W and so on... only at
operating temps due the Ws flow equally as 30 grade...
Shear
Shear Stability is a measure of the amount of viscosity an oil may
lose during operation. Oil experiences very high stresses in certain
areas of the engine such as in the oil pump, cam shaft area , piston
rings, and gears or any other areas where two mating surface areas
squeeze the oil film out momentarily... but technically speaking as
our oil shears down we don't see elevated wear rates because oil
analysis shows as viscosity shears down the flow goes up and the
concept of lubrication states the greater the flow the greater the
protection...
Blackstone's reporting confirms there are no reason to fear the shear...
its harmless because as our oil shears flow increases... increase flow
is desirable because our oil serves as a "wall" only when it is constantly
FLOWING between parts keeping them from touching.
Got some SAE or similar valid links that show this claim?
It all depends on what the start-up temperature is. That's what the "W" rating in the oil grade is all about.
You do realize that there is always an oil film left over on parts after the engine is shutdown that can maintain enough lubrication while the oil starts flowing from the pump. And that a positive displacement oil pump will deliver the same oil volume to all part of the oiling system as long as the oil is pumpable - meaning the pump intake can flow oil adequately, which is again what the "W" rating is all about. Also, if the oil filter ADBV keeps the oiling system full of oil like it should, then the time it takes the oil to start flowing is very short. Why aren't vehicles wearing out so much faster in cold climates like Alaska and Canada if 70% of engine wear is from cold starts? You'd think that if cold start-up caused so much more wear that Alaska and Canada would be piled high with worn out vehicles.
A lot wrong with those claims in bold. The oil flow volume doesn't go up when it shears down and becomes thinner. The "wall" of oil is they (or is it you) are referring to is apparently the film thickness of the oil layer between moving parts. That oil film will be there as long as there is an adequate supply of oil being supplied to the moving parts. And the thickness of that oil film is dependent on the oil viscosity and relative speed between the moving parts. Once the supply of oil is below the minimum volume of oil to provide lubrication protection, then that is when the film thickness (MOFT) goes to zero and wear starts happening from metal-to-metal rubbing.
The positive displacement oil pump must be the most misunderstood component of an oiling system - seems a lot of people just don't get how they work. If the oil pump is not in pressure relief, which it will not be when the oil viscosity is lower and the oil pressure lower as the oil viscosity decreases, then the SAME oil flow volume will exist regardless of the oil viscosity. The oil pressure will increase if the viscosity is higher and the flow remains the same.
Blackstone doesn't "fear the shear" (or is that you) because they most likely don't see many UOAs where the people ran oil that was way too thin, either from shearing way too much and/or running an oil that was too thin for the operating temperatures (ie, like someone running xW-20 on the track without an adequate oil cooler.
If someone took the claims literally, they would want to run a 0W-0 oil "because the thinner the better" ... but that's not true at all when talking about the required film thickness between moving parts to give adequate lubrication.
Don't use Castrol Edge Synthetic, it made the wet clutch in my ATV slip and damaged it so it would slip when cold until the oil warmed up with Rotella t6 5W40 . I now use Rotella t4 15W40, and it doesn't seem to slip anymore, even when cold.
Quote Amsoil
60% of total engine wear occurs during cold start up
conditions before oil can circulate through the engine...
Quote Lake Speed Jr certified lubrication specialist at Driven Racing Oil.
“While a thicker viscosity grade is a workable solution, remember that
70 percent of engine wear occurs at start-up, so a higher viscosity
grade actually causes more wear, and we have used oil analysis that
shows this,” says Speed.
Quote 540Rat
"Thinner oil flows quicker at cold start-up to begin lubricating
critical engine components much more quickly than thicker oil can.
Most engine wear takes place during cold start-up before oil flow can
reach all the components. So, quicker flowing thinner oil will help
reduce start-up engine wear, which is actually reducing wear overall."
Quote Frank McCowan, former Electrical /Mechanical Small and Large Equip.
Mech at Washington Metropolitan Area Transit Authority...
Listen to Jim Trainers answer below, it is mostly accurate. most
engine wear occurs during not only the first few minutes, but in the
first few seconds from when the engine is started.
Quote Jim Trainor, diy car maintenance guy
"The oil pressure takes a moment to come up and it takes a moment for
the oil to start circulating. There are bearing surfaces in your car,
called “journal bearings” that are quite literally two pieces of metal
separated by a film of oil that is delivered in under pressure in a
continuous flow. These surfaces do not touch when the engine is
operating normally. Other bearing surfaces, such as cam followers, and
piston rings, do touch but are subject to a continuous flow of
lubricating oil. When you start the car there are a few moments where
the oil is absent from these surfaces. Hence increased wear occurs."
Quote EAA ( Experimental Aircraft Association)
"When we first crank the engine, there's no oil pressure and the
crankshaft cranking speed is pathetically slow. The conditions for
hydrodynamic lubrication simply do not exist. Consequently, there is
metal-to-metal contact between the journal and the bearing, and wear
is inevitable."
The point of the photo is to graphically show the different rates of
flow between 0W 5Wand 10W... On a day with outside temp of 104F the 0W
still flows quicker during start that either 5W or 10W...