Power Valve 'overflow'?

[buck_y_lee]

Power Valve breather and Damaged Tranny Case

What is the overflow pipe that apparently comes from the powervalve?

I dropped my bike with force on a rock yesterday and the tranny seemed to take some impact. I picked it up and noticed grey fluid all over the ground. It looked to me like gearbox oil, however it seemed to be coming from that overflow pipe. I am worried that I've busted something inside, because the case seems ok. But having said that, the bike seems to run fine. I will dump my tranny oil during the week and and check it for metal, but I am confused and worried about the grey stuff that seemingly spewed out of the overflow.

Any ideas?

 

[marcusgunby]

Its a vent for the pv you normally get black goo from them not gray-gray suggests water as well.

 

[Stenmash]

When my bike gets upside down (seat is lower then the tires), crank case oil comes out of one of the vent tubes. I do not know if it is from the Power Valve though. Happenes everytime though and gets oil all over the engine and rear shock.

I was told that is what my bike does (KTM EXC 250).

I would drain the oil and maybe strain it to ensure there is no major debris. If it is clear then run it.

 

[gwcrim]

:joke: Here's to hoping that your bike isn't upside-down very often! :joke:

 

[buck_y_lee]

When my bike gets upside down (seat is lower then the tires), crank case oil comes out of one of the vent tubes. I do not know if it is from the Power Valve though.

Well, that's how it ended up - seat downhill.

But this is a two stroke - should only be fuel (+ 2 stroke oil) in the crank case. So anything out of the powervalve breather should be either black spooge or unburnt fuel, right?

The grey is scaring me. I killed the engine straight away, so I don't think it's indicating water. I would guess that it would have taken some time for water/coolant to mix with the fuel in the crankcase. In any case, it seemed more like tranny oil than fuel, spooge and water.

So this leaves me thinking that somehow tranny oil has made its way into the crank case, or that it has exitted from somewhere other than the powervalve breather.

I am not familiar with the structures of the crank and tranny, but I would assume that the chances of oil transferring between the two are fairly remote. But I cannot locate a crack on the underside of the tranny, so it doesn't seem to have come from there either. Maybe I've knocked the drain plug. The thread on that wasn't the best.

I haven't been able to drain the tranny or radiator yet (damn work). I'm just guessing at scenarios really. I would appreciate some comments on the transfer of oil between the two cases from those familiar with the structures.

Thanks,
Buck.

 

[buck_y_lee]

editted the title

 

[uts]

Gear oil usually gets into the crank case via a busted rh crank seal. This then gets drawn into the cylinder and possibly out the power valve overflow. But it usually get's burt into spooge in the cylinder and isn't grey when it gets to th pv. Also if this were the case your bike would be blowing heaps of smoke and probably fouling plugs. The transmission has an overflow/vent to, and oil does tend to come out of there if the bike is seat down. I think this is what is happening in stenmash's case.
If I were you I would ride the bike then turn off the fuel and run it dry. Now lay it down and observe. You will probably see that the oil comes out of the tranny tube and all is ok.

 

[buck_y_lee]

The seals have all been replaced recently, so the chances of a bad seal are slim.

I never realised the tranny had an overflow or vent. I shall take a look tonight.

Thanks for that uts.

 

[buck_y_lee]

I assume that if it had one, the transmission vent would be visible externally and that it would be towards the top of the casing, right?

Well, I can't find it and my Clymer manual makes no mention of it either.

 

[marcusgunby]

Maybe the tranny vent goes to the pv vent?

 

[uts]

I assume that if it had one, the transmission vent would be visible externally and that it would be towards the top of the casing, right?

Well, I can't find it and my Clymer manual makes no mention of it either.

Maybe your bike aint got one. On mine it comes out of the top of the case near the back of the tranny and the tube goes down near the rear shock.

Where is that gray stuff coming from :bang:

 

[buck_y_lee]

I wish I knew :( Oh well, good luck to me. Thanks lads.