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Oil leaking from under my bike (yz85)

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I recently got a yz85 that starts one kick new piston in it and it can idle forever sometimes cold start without choke. I left it to idle today for 3 min and around 4 minutes I see oil leaking from a tube, why is this happening?

 

 

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Possibly crank breather dripping excess oil from being too rich. If you can start without the choke it’s rich. Idling is loading it up.

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14 minutes ago, dbart250 said:

Possibly crank breather dripping excess oil from being too rich. If you can start without the choke it’s rich. Idling is loading it up.

engine oil or tranny oil?

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A 2-stroke's engine crankcase does not have a breather (think about it, it would become a source of air leak)

the gearbox cavity on the other hand does have a breather hose, it may leak out if severely overfilled.

 

Does it feel & smell oily or more like gasoline?

Follow the hose that leaks and see where it leads to, it's either the gearbox or the carburetor.

 

Float level too high also may leak out fuel when the bike is tilted.

It may also explain why the engine starts easily when cold and runs rich

as a higher level also richens all metering circuits.

 

YZ125 and YZ250 commonly leak excess unburnt premix thru the powervalve breather hose,

you can rule this out as the YZ85 does not have an exhaust powervalve.

 

 

Edited by mlatour
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A 2-stroke's engine crankcase does not have a breather (think about it, it would become a source of air leak)
the gearbox cavity on the other hand does have a breather hose, it may leak out if severely overfilled.
 
Does it feel & smell oily or more like gasoline?
Follow the hose that leaks and see where it leads to, it's either the gearbox or the carburetor.
 
Float level too high also may leak out fuel when the bike is tilted.
It may also explain why the engine starts easily when cold and runs rich
as a higher level also richens all metering circuits.
 
YZ125 and YZ250 commonly leak excess unburnt premix thru the powervalve breather hose,
you can rule this out as the YZ85 does not have an exhaust powervalve.
 
 

My mistake. I was thinking powervalve and missed it was an 85. Apologies.
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Perhaps a feature on future models of the YZ85 as the recently unveiled all-new 2018 YZ65 is equipped with one.

Edited by mlatour

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1 hour ago, Nicole Froneman said:

Hey there. I have a question about oil leakimg from a yamaha yz85 2009. Is it meant to leak oil? 

 

Where is the oil leaking from Nicole? A photo or explanation of location will help. Oil can leak from exhaust spigot (un-burnt oil/fuel mix), also, transmission oil can leak from a bad seal, and/or drain plug seal. 

So, photo up..

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