2 stroke dirtbike transmission oil?

Question

I have a KTM 360 2stroke dirtbike..... the manufacturer recommends i use SAE 30 oil... some people, including the dealership, told me to use honda hp trans oil, which is SAE 80w/85W..... is this OK or will it mess up the bike? Also, why are they telling me to run this thicker oil?

Answer 1

Gear Oil and Engine Oil are measured on 2 entirely different scales

Multi-vis tested at 0*
Single weight at 220*
Gear at 100*

85weight Gear is is approx same fluid density as SAE30 Engine

Comparrison(Aprox,,I cant recall exactly)
ENGINE Oil (Straight SAE) vs Gear Oil
5~10 = 75W Gear
15~20 = 80W Gear
30= 85W Gear
40~50= 90W

Actually ,There's a lot of Overlap on the 2 different scale.
Not directly proportional.
Kinda like comparing Centigrade Temp and a Fahrenheit Temp Scale.

Frankly,,I do not know anything specifically about Honda's oil.

Curious though that its called TRANS Oil ,and graded on GEAR oil scale

Gear Oil has far different chemistry that Engine Oil

While Engine Oil is not very satisfactory in many GEARBOXES,,,
it is nonetheless "Compatible",,at Minimum it's Chemically Benign.

You can pour Engine Oil into any Manual Gearbox and at least NOT HURT it by the oil's mere Presence.

Conversely,,,
GEAR OIL is near universally "dangerous"in an Engine's Crancase.
It quickly becomes extremely corrosive in the presence of combustion by-products.

Gear Oil should NEVER be put into a Engine.
Not even in Emergencies,,,unless it's near a "Life or Death" matter and You GOTTA go.
But you can just about Expect the Engine to be "Sacrificed for the Cause.
If thats ever a necessity for whatever reason to Use gear oil in an engine,,CHANGE and FLUSH ASAP.
It goes Way Acid almost immediately,and within a few DAYS it starts eating

SOME certain ENGINE Oils are actually Superior to Gear Oil in Some GearBoxes.
Even where actual Gear Oil is OEM specified.


Engine Oils use zincs and calciums as EP additives ,
which do not break down to Acids.
They're alkalies,and include Other additives intended to eliminate the corrosives/acids in engines.

Gear Oils use sulphurs,,,which DO go acidic in presence of combustion by-products.
(As in Sulphuric Acid--aka Battery Acid,,,who wants their crankshaft swirling around in a Sulphuric acid bath??LOL)

Gear Oils additives have been proven to IMPROVE wet clutch performance.
The Sulphur/Phosphor Compounds in particular.

Engine Oil's Zinc-based Anti-Friction stuff (ZDDP) is the root of the current Phobias & Fears about "Car Oil" and it's affect on Wet Clutches.

Bike Clutches lived Long & Strong for Decades with Zinc Filled Car Oils.

And with RACING OILS having Such HIGH quantities of ZDDP,,,,to read the ingredients left a person wondering if they were gonna have to Scoop the Oil outa the can.
20~50~100 TIMES the current average Zinc content.

What Happened between Then & Now??
2 Primary things actually.

1) Elimination/Minimization of ASBESTOS content in the Friction Material Compounds.
2) Drastic Reduction(and the impending Elimination) of ZINC
in Engine Oils

OLD Formula Clutches Loved Zinc
NEW Formula Clutches Hate it

OLD ones can well tolerate Low/No zinc oils.
There's always been Oils which had No Zinc,,
but used alternative anti-friction compounds instead.

Many,Many NEW clutches can barely tolerate Zinc at all.

So while so many folks Parrot the Perils of "Car Oil",,
Reality is that Bikes from 70's ~80's,and even Early 90's
are Better Off with HI zinc oils.

Also important to realize that any "threat" is Limited to CLUTCH.
Anything with a Dry Clutch,,or an isolated clutch---separate from Motor's oil supply,, can use Zinc oils just fine.
And are actually way better protected by it.

So there's NO "Universally Applicable" rule about Bikes and Oils.
All depends on What's What
........................................
Your interest is about Gear Oil.

Your KTM has TOUGH Gearbox,,no doubt.
But it AINT a Diesel Truck Gearbox.
It aint even a 350Hp 4,000 Lb Passenger Car gearbox.

Which is precisely what GEAR OILS are designed for.
Not motorcycles.

That's a Large part of the reasons why "ENGINE OIL" is "Ideal" for Bike Transmissions in so many instances.
Darn near Universally.

Every single Jap Bike from early 60's to 90's at least ran their Trans' on MOTOR OIL
10w-,,and 20w- Multi Vis oil,,,which is damn near "Not Oil " at all,,,it has such low amount of Base Stock.

And thats covering 150 Lb ,, 1/2 HP per CID,,,45mph,, Honda Cub 50's,,,
to 500~600Lb,,2HP++ per CID,,150Mph+++ Multi Cyl Monster Bikes.

OBVIOUSLY,,,"plain vanilla Car Motor Oil" has proven itself in Bike Transmissions quite well.

Here in 21st Century,,,with All the Techno Advances in Every Engineering and Chemical Science,,,Metallurgy,,Manufacturing Processes,,etc....
And with ALLLL That applied to Modern Hyper-Bikes,etc....

You can go Drain the Transmission of probly 90%++ of the ALL the Bikes in the entire World,,,
and find "Just Plain Ol' Motor Oil".

That includes Modifieds,,Racing Bikes,,stuff in extreme duty apps.
Sure,,they Choose "Exotic,,SPECIAL......Motor Oil".
Still JUST motor oil though,,aint it?

I personally do Not know of a single instance where any program has required "Upgrade" from Motor Oil to Gear Oil.

........................
The most INTERESTING thing about Bike transmission oil
to me ,,,and something that remains a Mystery,,,
is the Use of ATF,,,Automatic Transmission Fluid.

Every single Property and characteristic of ATF is OFF-THE-CHART Superior to Anything else commonly available for Bike Transmissions and clutches.

It's Use and "Popularity" has faded in/out over the years.
ZERO horror stories.
Not even a Hint.

Auto Trans's have more in common with bike boxes than ANY 2 other automotive devices or mechanisms.

If anyone wanted to use an ULTIMATE TORTURE TEST Machine to perform In-Service Testing of Transmission oils...
Away from the TestTubes and Computer Models,,,

and Test it Out of the Lab,,,and on the Tarmac,the Desert,The Mud,The Woods and the Freeway instead....
I can't imagine a More ABUSIVE,HOSTILE Physical Environment than a common,average Automatic Transmission.

ATF has to live under such exagerated conditions it's MInd Boggling that an "oil" can even function at all.

What ELSE is universally equipped with an outboard COOLER>
Not Engines,rear ends,manual transmissions.

Centrifuges are used to separate liquids.
A Torque Converter is a Fine Centrifuge.
I'd LOVE to visit a Lab with a 300~400 Horsepower,5,000 RPM,,,10~12" Centrifuge.
That'd Sling the Stink offa Skunk and the dimples offa golfball.

MILLIONS of people "Drive " such a "centrifuge "everyday,,
Thrashing the SAME oil for YEARS,,5~7~10 YEARS,,100~150,000 Miles

Try that with Motor Oil,,you'd squeeze out Dinosaur DNA before ya got to work on a daily commute.

ATF has nothing but a SCREEN for a filter.
It's a Good Screen,,obviously.
Because it has to function for YEARS in Hair Fine Passages,Orifices,Clearances.

Heat,,,it has to protect 2 handfuls of Plastic washers and elastomer seals,O-rings,,etc.
Any Nick,Crack,Hardening,Collapse,or undue Memory>Heat Set of even a FEW Thousandths make the WHOLE TRANS a NO-GO.
ATF handles it.

Shear?
What does a Gearbox in a Car or Bike have that even applies a Percentage of the Shear that a Torque Convertor does?

The Whole CAR is DRIVEN by a Fluid Cushion.

And THEN that same oil gets captured in the Planetary Shell,,,and chopped up by Spiral Gears.
Auto Trans Gears in a 1-Ton Pickup are 'bout same size as avg 500~600cc BIKE

Slipping Clutches DESTROY more motorcycle Oil than everything else put together.

Auto Trans spend most their life Slipping.
But it AIN'T a Simple Slip,,,like we do with a Bike Clutch at the start off from a stop.

A/T Clutches have a Programmed Overlap between Gear shifts to establish some desired shift quality/characteristic.

They are Actually in "2 Gears at One Time".
One Band/Clutch Fades OUT,,while another Fades IN to engagement.
It's a Compound Slip,,,Under Applied Power between Drive/Driven.
EVERY SINGLE shift of it's entire Life.

Then there's also it's trochoid Oil Pump,,,sqeezing and grinding on the oil.

MUCH of the bearing surfaces,,and shaft bearings/bushings are merely SPLASH Lubed.
As Hot and Crushed and Ground-up and OLD as ATF gets,,,,
It gets slung around here & there on Heavy Load ,,Lube Dependant components & surfaces..
And goes for 100,000 Miles without missing a lick.

Take 'em APART at 10 Years/100,000 Miles,,,and inspect all the parts......
and Most of the MOTORCYCLE Sized Gears,Bearings,Bushing,ThrustWashers,ClutchPlates from the Multi-100 HP,,,Several TON vehicles are all still surprisingly In-Spec.

ATF is Soooo Freakin' Superior for GEAR,CLUTCH,SEALS it's one of those "Too Good to be TRUE" things.

Car Makers COULD HAVE just as easily used MOTOR OIL,,or Light Mineral Oil in A/T's right?

Sure,,,Fill an Automatic with some SAE 10W,,,or any 0w-10.
It'll WORK.
It just wont Last.
Mechanical life Drops from DECADES down to Weeks,,or even DAYS.

Another bit of trivia about the abuse ATF is designed to endure compared to Engine Oil.

Avg V-8 Car Motor holds 5 Qts of Oil.
1 is in the Filter at all times.
WHERE Else is the oil while Running?
The Galleries /Oil Passages to Lifters & Crankshaft,,,
IN the Hydraulic Lifters,,
and IN the Crankshaft passages,,
and a little in the pump body.

EVERYBODY has Added a Quart of Oil.
MOST people have added 2.
MANY folks have added 3 Quarts of oil to a 5qt Motor.
And ANYBODY who has serviced a BUNCH of cars can attest to MANY,MANY Instances of Adding 4 Quarts of Oil to a RUNNING CAR,,,which suffered no apparent damage.

Dont Try This at HOME,,,but it's an Absolute,Known Fact that
TONS of Avg American 5Qt Car Engines will FUNCTION and SURVIVE when 4Qts LOW.
Even I myself have a Tuff Time stating,,,"A Car will Run on a SINGLE quart of Oil"

STUPID,,but TRUE.
It happens Every day

I've had more than a Couple which adding 4 qts would NOT reach the Full Mark,,,and 5qts barely went Over the Full Mark.

Point is this,,,
A Car has an Abundance of Reserve Oil Capacity beyond the Bare Minimum required to at least RUN .
3~4~even 4.5? Qts LOW,,will start>run>go down the road.

So 5 Qts Normal Level is 2~3~4 TIMES what's required for Minimum Function.

Compare to an Auto Trans fluid capacity.
20~25 Quarts,,,4~5 Times as much as Engine's Oil capacity.

Go Drain 2 Qts outa an Automatic and see how far ya get.

80~90% LOW on an Engine,,it Still Works
10% Low on an Auto Trans,,and it DONT
20% Low SURELY wont.

Think about that,,and implications of that in terms of Load,Abuse,Capacity,,and general,overall LUBE supply.

The Engine lives with an ABUNDANCE,,a SURPLUS of Lubricant

Auto Trans Really has "None to spare".

Or Put another way,,,
MOST of an engine's oil is working Part Time

ALL of an A/T's oil is working FULL time.

In Comparative Terms,,,For an A/T to have the Same SURPLUS of Lube that an Engine Does...
it would need to have about 100~125 Quarts.
Sounds Crazy,huh?

The SURPLUS in an Engine compared to it's BARE Minimum,,,would fill a Milk Jug.

That Same Ratio in an A/T would fill Half a 55 Gallon BARREL.

Can't help but wonder How Long an A/T would Last
if IT TOO had such a Surplus Supply ratio of Bare Functional Minimum-To-Surplus Capacity

25 GALLONS of ATF vs the usual 25 QUARTS

Then there's the 3~5,000 Mile Recco'd Change Interval on Engine Oil,,,while Most ATF dont EVER get Changed at all.

That Sez something about ATF's Durability and Lubricity compared to Engine Oil.

Always leaves ME wondering why we have Friction Clutch and Gear sets that we insist on using Engine Oil in which AINT designed for that application,,

when we have Specifically Developed Lube for
Friction Clutches and Gear Sets.
That's PROVEN itself for way over Half a Century,,and literally Billions of Miles of Reliable Service in far,far Heavier,More Extreme Service than ANY motorcyle will ever possibly see.

I use it in everything it's suitable for use in.
Anything with a wet clutch /transmission isolated from engine oil.
For close to 50 years now.
For whatever that's worth.

Final Word on Oil:
It's Your Motor,,use whatever makes you happy.
At MINIMUM,,stick with a single weight SAE Motor Oil.
Besides that there's all sorts of Snazzy stuff out there .

Plain Ol' Motor Oil has done Double Duty and a decent job "forever" in bike transmission/clutches.
It works,,ya know??
Always hard to argue against whatever works.
Ya can't go too far wrong.

Have Much Big Fun this summer on that thing!

Answer 2

When I had my Harley I think it called for a 60W in the transmission. I was in Texas at the time and many Bikers said I should run a heavier weight in both the Transmission and Engine because of the heat. So, I used a 90 weight in the ransmission and a 50 weight in the Engine and used a little "Marvel Mystery Oil" in my gas. Never had a problem. But, I did notice it shift hard at first, but, after it warmed up it did well.
Of, course you not need marvel mystery oil as your a 2-stroke and have oil mixing with your fuel.
I can not say a "Why", and it may be more to your discretion. But, this what I did.

Answer 3

2 Stroke Gear Oil

Answer 4

This Site Might Help You.

RE:
2 stroke dirtbike transmission oil?
I have a KTM 360 2stroke dirtbike..... the manufacturer recommends i use SAE 30 oil... some people, including the dealership, told me to use honda hp trans oil, which is SAE 80w/85W..... is this OK or will it mess up the bike? Also, why are they telling me to run this thicker oil?

Answer 5

85 weight gear oil made specifically for 2 strokes is what i always run in my 2 stroke race models. Try golden spectro oil, it works the best for me. You want thicker because it doesn't break down so fast from the heat that the bike creates during heavy riding.

Answer 6

I have a KTM 300 MXC. for the last year and a half I have been running Chevron ATF DEXRON®-III

but almost any DEXRON®-III approved ATF might work.

An International Six Days medalist suggested I try it. It's what he runs in his bikes, and is kids bikes (all racers)

lighter, less friction, more heat dissipation, and really REALLY makes the clutch work properly.

CAVEAT! I change my tranny oil every other ride. It comes out looking fresh, but I still change it every other ride.

Answer 7

For the best answers, search on this site https://shorturl.im/awDkj

Because they think everything is a 4 stroke. Dont use it or you will destroy your KTM. Just put in the SAE 30, and ride on Bro.

Answer 8

sorry but your mistaken it is a thinner oil, will hep better in the lubrication of the gears bushing etc....listen to them

Answer 9

Use what the manufacturer suggests.