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Yz125 tranny fluid

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I got a 2000 yz125 that has always been ran on atf(going to find out the type tomorrow), anyway when I changed the oil I switched to Nulon multi vehicle semi synthetic (Allison C-4, mercon, Dexron 3 and caterpillar T0-2)

Now I have a few questions as to if I should swap to just Castrol atf Type F, becuase its cheaper

and im not sure but I think after I switched to the Nulon oil, I have a countershaft seal leak, which I'm changing the seals tomorrow

Now the Nulon oil couldn't be too thin could It and seep through causing the leak(or I could of just blasted it too hard with the pressure washer because I know I was trying to get mud out of the chain gaurd) and should I swap to type F or stick to the Nulon

Sorry for the long question this is my first bike and im slowly learning it all

Cheers

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Plain old ATF-F is the best you can get. Why switch?  Here we have big stores like Walmart that carry no-name store brands so I use that. Not sure what sources you've got in Australia, but Just find the cheapest available.

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Check if the Nulon is JASO rated (wet clutch) to avoid possible clutch slippage issues, if not perhaps reconsider using it.

 

ATF,  Motorcycle specific 10W-40 (JASO), 80W or 85W MC gearbox lubes or even some heavy duty engine oils (15W-40 Shell Rotella, also JASO rated) are all fine to use.

 

Most often comes down to clutch operation 'feel' preference, reason why ATF is sometimes preferred.

 

I've tried them all and have gotten best shift and clutch feel with ATF in my YZ125.

 

Your seal leak is not related to the oil, you can probably blame the pressure washing for that.

Edited by mlatour
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Switching the oil did not have anything to do with seal failure. Really, oil has been jawed about over many of beer and bench racing. Find what you like and run it. There are many choices and opinions. So here is mine, I run 80/85 Honda HP in all my transmissions, is it better than the rest? NO...

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Run the fanciest oil you can afford to change at a good interval. I'm poor so I use 10w30 Supertech from Walmart and change it every couple of rides.

 

Cheap oil changed frequently > High $$ oil changed infrequently.

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Run the fanciest oil you can afford to change at a good interval. I'm poor so I use 10w30 Supertech from Walmart and change it every couple of rides.

 

Cheap oil changed frequently > High $$ oil changed infrequently.

 

How would you know that expensive oil is actually better?  I do agree however with the rest of your approach--I buy whatever 10w-40 is on sale and change it every 4--5 rides/races in my 125s.  All the clutch slipping gets a lot of stuff in the oil quickly.

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That's the thing about using a more expensive oil, people tend to leave it in longer since it's believed to be a 'superior' lubricant (plus the extra $$ spent)

 

A gearbox has no oil filter, the longer you leave it in the longer metal particles from the gears and clutch debris get circulated over and over causing even more wear.

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That's the thing about using a more expensive oil, people tend to leave it in longer since it's believed to be a 'superior' lubricant (plus the extra $$ spent)

 

A gearbox has no oil filter, the longer you leave it in the longer metal particles from the gears and clutch debris get circulated over and over causing even more wear.

No way man! Keep it in for 100,000 miles, then run it through a cheese cloth and put it back in. Oil never breaks down...

Sarcasm... Hehe, haha...

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A gearbox is much different than an engine crankcase. A gearbox can run a really long time without even needing an oil change. I run ATF and change it about two times per season. Basically the only reason to change it at all is the clutch wear introduces fragments from the friction plates. But there is no way this material is going to seriously impact steal gears and bearings. It is normal to get a little bit of steal powder rubbing off the gears from rough shifting/grinding, but if you are seeing metal significant fragments in you oil changes you may have something wrong inside.

 

My opinion is your oil can tell you how often you need to change it by inspecting it at every oil change. If it comes out looking like new with no sediment you are changing too frequently. One very important thing to pay attention to is if your oil ever comes out milky (or pink froth in the case of ATF), because this indicates water is getting in. This happens frequently when water pump seals wear and must be fixes asap.

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