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2004 YZ125 dripping black oil


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Hey everyone, so today I noticed my yz125 was dripping black oil. I looked aroumd and cleaned everything up and I saw this little black plastic or rubber piece that's above the water pump, so that's resposible for the dripping oil, has anyone ever encountered this issue? It's been running down the side of the casing out to the petcock and I thought it was something severe so please help me with this.ImageUploadedByThumper Talk1419440713.307381.jpg

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You mean below the PV cover most likely. That is quite normal. There is an oil seal where the PV shaft goes into the cylinder which need to be change.

If the jug is old there is a member on TT which has done a bushing for it.

Ohh ok, that's probably why when I punch it it doesn't sound like way up there, only when I'm in higher gears
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You mean below the PV cover most likely. That is quite normal. There is an oil seal where the PV shaft goes into the cylinder which need to be change.

If the jug is old there is a member on TT which has done a bushing for it.

I don't know exactly what it looks like, could you find a picture for me please?
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That picture shows the housing/cover for the power valve *linkage*

(from the governer up to the cylinder)

and not the power valve cover that is on the front of the cylinder.

 

If that seal is leaking, it is probably transmission oil. (If your oil is that BLACK, it's way overdue for a drain/refill !)

 

It's also possible that the PV cover is leaking so badly that it's running down into that area of the engine.

Edited by mlatour
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That picture shows the housing/cover for the power valve *linkage*

(from the governer up to the cylinder)

and not the power valve cover that is on the front of the cylinder.

If that seal is leaking, it is probably transmission oil. (If your oil is that BLACK, it's way overdue for a drain/refill !)

It's also possible that the PV cover is leaking so badly that it's running down into that area of the engine.

I changed it yesterday though. And since my clutch is &%$#@!ed up I haven't ridden it in a few days so it settled, but do they really use transmission oil in dirtbikes?
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Most manuals will say to use Yamalube 10W40 motorcycle oil.

Some people use Rotella-T 15W40, this and motorcycle branded oils have a 'JASO' specification

that's preferable for wet clutch systems like dirtbikes compared to regular motor oils.

 

Some like me prefer a lighter ATF (automatic transmission fluid) fluid like :  Type-F or Dexron III

(I think a Dexron equivalent might even be the 'OEM' fluid in KTM 2-strokes)

 

2-stroke transmissions aren't too picky, it's often up to rider preference for clutch engagement 'feel',

I ride in cooler weather and anything thicker than ATF doesn't shift well.

 

Sounds like you need to pick up the manual or at least find it online.

Edited by mlatour
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I changed it yesterday though. And since my clutch is &%$#@!ed up I haven't ridden it in a few days so it settled, but do they really use transmission oil in dirtbikes?

hell yeah.

 

type f is supposedly the better of them as dextron2 is a bit different, dont ask me what the differences are, just read somewhere that type f is the better of the 2.

 

and i might be wrong, but we all know the internet does not lie... :moon: 

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hell yeah.

type f is supposedly the better of them as dextron2 is a bit different, dont ask me what the differences are, just read somewhere that type f is the better of the 2.

and i might be wrong, but we all know the internet does not lie... :moon:

I mean, Transmission oil in powervalves
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The oily accumulation you get in the PV cover (in front of cylinder) and out the vent is un-burnt premix going out the exhaust and around the powervalves, not gearbox oil.

 

The oil leak picture you posted in your 1st post here isn't the PV cover but the powervalve's linkage cover, between the side case and the cylinder.

The linkage runs from the governer (near the water pump) up to the cylinder's PV cavity, oil that leaks from there is most likely gearbox oil.

 

The difference between Type-F and Dexron are the friction additives,

both will work very well in our transmissions but Type-F is an old-school favorite because

it 'grabs' a little more and is less prone to clutch slip. Type-F is not as popular in the automotive industry

as it once was so it's sometimes hard to find in part stores.  Dexron will do fine though.

 

Also a plus for ATF is that it's cheap, you can replace is more often to flush out clutch particles and other debris and unlike regular motor oil,

it's always compatible to use in a 'wet clutch' systems. Only motor oils with a 'JASO' classification are compatible for clutches.

Edited by mlatour
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The oily accumulation you get in the PV cover (in front of cylinder) and out the vent is un-burnt premix going out the exhaust and around the powervalves, not gearbox oil.

The oil leak picture you posted in your 1st post here isn't the PV cover but the powervalve's linkage cover, between the side case and the cylinder.

The linkage runs from the governer (near the water pump) up to the cylinder's PV cavity, oil that leaks from there is most likely gearbox oil.

The difference between Type-F and Dexron are the friction additives,

both will work very well in our transmissions but Type-F is an old-school favorite because

it 'grabs' a little more and is less prone to clutch slip. Type-F is not as popular in the automotive industry

as it once was so it's sometimes hard to find in part stores. Dexron will do fine though.

Also a plus for ATF is that it's cheap, you can replace is more often to flush out clutch particles and other debris and unlike regular motor oil,

it's always compatible to use in a 'wet clutch' systems. Only motor oils with a 'JASO' classification are compatible for clutches.

Right now I'm running ATF and if I changed the oil two days ago and I haven't taken it out recently, why would it be black? And I'd assume since powervalves are connected to the exhaust it would be the spooge shot out of the engine
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