Oil Leak Under Stator

EZRider76

Member
Feb 23, 2012
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So, with everything else I've been doing, a couple days ago I noticed some oil on the bottom of the engine. I snugged up the drain plug, I pulled the clutch cover off and cleaned the gasket and the mating faces to make sure there wasn't dirt in there. Then, I pulled the stator cover off and it appeared that the oil was coming from in there. I cleaned it out as good as I could, wiped it all down and put the cover back on. Today, while just riding around the yard checking the new main jet, I pulled in to do a needle change and oil dripped to the ground. I pulled the stator cover off and sure enough, it was soaked with oil in there. I see, from looking at diagrams, there is an oil seal under the stator.

My question is this, how much of a PITA is that to change? Also, my leakdown test was perfect a week ago, now I'm leaking, does the leak down not test the bottom end? Could the leakdown test have caused this? I only used 7lbs of air.
 
7psi is what you should use otherwise you can blow the seals.

There are 2 ways to perform the leak test, from the carb boot or from the spark plug(not recommended by me).

Which way did you do it?

Leak down test looks for leaks in the crancase, including seals.

It is an easy fix.

If you have a leaky seal on the stator side, no wonder you have been chasing that needle!
 
I left the plug in, sealed off the exhaust flange and had my tester at the intake. So, could I have blown the seal with only 7lbs of air? I have replaced the seal around the shift shaft already because it was leaking out of there, actually, I replaced the shift shaft when I did the seal too come to think about it.

I am going to do another leakdown here in about a couple hours, after dinner, just because I can and check. Should there be oil in the crankcase when I do it, or should I drain it?
 
You are confusing the crankcase with the gearbox.

There should be oil in the crankcase but there is no way to drain it.

If there was air coming from the shift shaft then you have a blown gearside seal as well, and maybe a blocked breather tube.
 
Oil wouldn't leak from the seal behind the stater. That is a crank seal. It's ether the shift rod seal or some kind of damage to the casing itself.
 
There should be oil in the crankcase but there is no way to drain it.

If there was air coming from the shift shaft then you have a blown gearside seal as well.

Even if he had a blown shift shaft seal how is it getting inside the stator cover?

He said he noticed it then later confirmed it was coming from inside the stator cover thats only one thing the crank seal.

Any why would you ever want to drain the oil from the crank shaft?

To ezrider get a puller and a set of seals and get at it.I:I
 
Oil wouldn't leak from the seal behind the stater. That is a crank seal. It's ether the shift rod seal or some kind of damage to the casing itself.

Not true!

The residual oil in the case could be getting blown out.

Ezrider does it smell like premix oil or the oil youre using in your tranny?
 
Oil wouldn't leak from the seal behind the stater. That is a crank seal. It's ether the shift rod seal or some kind of damage to the casing itself.

I beg to differ, there is always some oil in the crancase to lubricate the innards,.

The seal is there for two reasons, to stop air getting in, and to stop oil getting out when the crancase is pressurised.

Although not common, bad seal here will let oil escape.
 
When I pulled the cover off the side of the engine to reveal the Fly Wheel and the Stator, then looked at the cover, there was oil on the bottom sealing surface of the cover. Then, when I peeked in to the fly wheel area, on the bottom side of the fly wheel, the oil trail was coming from up behind there. When I looked at exploded view diagrams, there is an oil seal there, that covers up the bearings and that the crankshaft goes thru. Check out this exploded view. CRANKSHAFT PISTON Yamaha BLASTER (YFS200M) 2000 OEM Parts - Cheap Cycle Parts I am thinking it is item 15 in this diagram.
 
I cleaned it out as good as I could, wiped it all down and put the cover back on. Today, while just riding around the yard checking the new main jet, I pulled in to do a needle change and oil dripped to the ground.

I don't see how the crank seal could leak that much oil that fast without being totally blown out and having a high rev problem.
 
I cleaned it out as good as I could, wiped it all down and put the cover back on. Today, while just riding around the yard checking the new main jet, I pulled in to do a needle change and oil dripped to the ground.

I don't see how the crank seal could leak that much oil that fast without being totally blown out and having a high rev problem.

Welp, either way, it sounds like the seal is blown out now and I won't be able to inspect anything else until I get a fly wheel puller and get in there. So, seals are cheap, I'll get one of those also.

EDIT: There isn't any high revving going on though.
 
Buy both side seals and change them both, may save doing it again later.

Prob could not hurt, every other seal has needed replacing.

so, I'm doing another leak down test and all seems good. the seal I'm looking to change must not have to do with the leak down test?