Gearbox oil for ktm exc250

[Furyos J]

Hi all,
ive been using motul full synthetic 2t gearbox oil 10-40 in my last two dirt bikes, change it every 6-7 hours, costs around $30 per litre,the cost never really worried me, altho it does add up over a year or two
Went out riding with some different mates yesterday, and one of them was doing g/box oil on a 2stroke ktm before we went out, he was putting in motul 4t oil, full synthetic 15-40 at around $70 for 4 litres, i asked him why and he said as long as it was for wet-clutch it was fine, he rekoned the 2t gearbox oil thing was a marketing ploy to get you to spend more $$ then needed.
They guy who told me this is pretty reliable and knows his stuff.
So is this true, does cheaper 4t oil work just fine in 2t gearboxs??
Thanks
J

[doddzee]

Ive got a 09 250x the manual says to use 15w 50 4 stroke engine oil. Always worked fine for me, usually change it every 7-10 hours

[noobi]

Short answer: Yes, it is fine, as long as the engine oil is designed for motorcycles (wet clutches).

Engine oil has components that make it resistant to fouling from combustion gases, gearbox oil doesn't.
Gearbox oil is generally 'less slippery', although can have the same viscosity rating, so it doesn't cause clutch slip.
Engine oil is generally 'thinner', so it can flow through oil galleries, however this behaviour can contribute to clutch slip.
They are NOT the same thing, and are designed to do very different things.

However, the oil is replaced before it begins to degrade enough to really make a difference. In 2 strokes it doesn't really make much difference as its only the clutch and gearbox it's lubricating. MR motorcycles run semi-synthetic Elf 4 stroke oil in everything.
I would be a bit more picky about oil in a 4 stroke.

[Rupe]

Short answer: Yes, it is fine, as long as the engine oil is designed for motorcycles (wet clutches).

Engine oil has components that make it resistant to fouling from combustion gases, gearbox oil doesn't.
Gearbox oil is generally 'less slippery', although can have the same viscosity rating, so it doesn't cause clutch slip.
Engine oil is generally 'thinner', so it can flow through oil galleries, however this behaviour can contribute to clutch slip.
They are NOT the same thing, and are designed to do very different things.

However, the oil is replaced before it begins to degrade enough to really make a difference. In 2 strokes it doesn't really make much difference as its only the clutch and gearbox it's lubricating. MR motorcycles run semi-synthetic Elf 4 stroke oil in everything.
I would be a bit more picky about oil in a 4 stroke.

My kxf's always had the 4t engine oil and that runs through clutch, gears etc. Never had a problem.

Now I'm back on a 2t I'm running atf dex 3 again. Never had. or seen any probs with that either, just change every 2-3 rides.

$30 a liter is a cost you can do without.

[gwynfryn]

atf is all i ever use. well proven and cheap enough to change frequently.

[Boo]

I run 4t oil with easter in it on my 2t motard, a notciable difference in shifting doesn't last any longer and it is expensive. I use tractor oil on my trail 2t, they use it for tractors with wet clutches. $20 for 4lts.

[Trials Rider]

Hi all,
ive been using motul full synthetic 2t gearbox oil 10-40 in my last two dirt bikes, change it every 6-7 hours, costs around $30 per litre,the cost never really worried me, altho it does add up over a year or two
Went out riding with some different mates yesterday, and one of them was doing g/box oil on a 2stroke ktm before we went out, he was putting in motul 4t oil, full synthetic 15-40 at around $70 for 4 litres, i asked him why and he said as long as it was for wet-clutch it was fine, he rekoned the 2t gearbox oil thing was a marketing ploy to get you to spend more $$ then needed.
They guy who told me this is pretty reliable and knows his stuff.
So is this true, does cheaper 4t oil work just fine in 2t gearboxs??
Thanks
J

Why do you change it every 6-7 hours, I could understand if you get water in it or racing where you are fanging the shit out of the clutch but for normal trail riding you should get 20-25 hour easy, there are no petroleum contaminants that you get with four strokes, it is only gears and clutch.

Read this article http://www.gasgasrider.org/html/gear...valuation.html

I use the Amsoil 0-40 in my gassa EXC300 which for all purposes is the same as KTM, I have found exactly what the article says, the Amsoil works very well and even at 25 hours is still fairly clean which is what I would expect.

[Furyos J]

Why do you change it every 6-7 hours,.

Pretty much cause thats what my mates i ride with rekon is a good time to change the oil.Its how often i used to change on my cr250, and i just kept the same interval for the KTM. I have to say, it usually looks quite clean when i change it, just the usual mettalic look to it from the clutch wearing.

[warewolf]

I was using Mobil 1 15W50 because I use it in all my 4T bikes. BUT... contrary to my expectation comparable dedicated gearbox oil (Motorex Gear Oil SAE 10W30) was quite a bit cheaper, presumably because it doesn't have all the combustion-fighting additives. Some years KTM says use 4T engine oil, some years gear oil, probably depends on their OEM oil "sponsor".

I'd change the oil in my 200EXC at 3-7 hours (book says 10) but it would be horribly black at as little as 4 hours due largely to the aluminium alloy clutch plates and possibly cork friction plates. Still felt good in the fingers (different to used 4t engine oil) but looked shocking. Did lots of 3-hour cross-country races so a fair bit of heavy going at times. Going all steel in the new clutch for a bit more flywheel and less crap in the oil.

[Trials Rider]

Pretty much cause thats what my mates i ride with rekon is a good time to change the oil.Its how often i used to change on my cr250, and i just kept the same interval for the KTM. I have to say, it usually looks quite clean when i change it, just the usual mettalic look to it from the clutch wearing.

I have two magnets to collect any floaties but same as you just a bit of fluff on them is all it gets, it would be interesting to test the oil and see if it was still at full specs at 7 hours, I suspect it would be

[Boo]

I change mine when it starts getting notchey on the tard, I get use to the timing on the gear changes, keep missing the changes or half change. Usually lasts about 11/2-2 hrs.
Soon as I get new oil in her, back to clean changes and good rides.
I feel guilty and change my trial, 7 hrs still clean.

[Pornstar]

atf is all i ever use. well proven and cheap enough to change frequently.

Yep, me too.

[Trials Rider]

Yep, me too.

ATF, how does it feel changing gear, I ask because it is very light in viscosity, is it notchy?, I can see it would be good for the clutch plates being light, would minimise any slippage.

[oldskool]

Used ATF in the 2 years I rode the GG300, didn't have a problem with it.

Now looking into the pro's and con's of using diesel engine oil for the 4T. Wwaay cheaper than motorcycle branded oil and has the same properties.

[Boo]

Tractor oil, they us it for there engine and gear boxes, $20 for 5 liters last time I brought some, I just checked. Agrip super tractor oil, can't get any cheaper then that