EC250 Leaking oil through powervalve cover
 

Hello!

My name is John and I am from Spain, I have recently discovered this forum so I decided to create an account!

I have an old EC250 from 2001 wich I enjoy ridding but I have some minor issues wich I would like to fix and learn in the process.

My gas gas leaks oil from left side powervalve cover, I have put a new gasket but still leaks oil, it is strange because leaks through inferior part of the gastket and through bolts hole, It is possible that cilinder's pressure is leaking through power valve?(see attached picture, that quantity of oil is after an afernoon riding with friends).

I have checked the vent tube and seems fine, but I cant see "where that hole goes" as i dont see any hole on the interior of the powervalve zone. Could the ventilation tube be clogged? Where is the entrance of that hole in the engine?

It is quite disgusting because sometimes I make little rides with normal clothes and my throusers and shoes get dirty with black oil. Moreover, I have plenty of friends with EC250 and EC300 and their bikes are always clean in that zone.

As far as I know my carburation is not perfect, usually when I check the spark plug is black, and to keep idling the idle screw is inserted all the way I think that low/mid range has much gas, high range feels great. I would like to improve the jetting but I have never taken apart a carburetor so I need to see some tutorials and learn first or find a good mechanic.

Thanks in advance!

EDIT: I add this link off google photos to see the attached picture with the best quality

https://photos.app.goo.gl/fiYqdTjDak6cd1de9

Looks like the oil is coming out the drain, does it have a hose on it running under the motor? Here is a pic of the nippl

There's also one on the bottom left that runs to a hose. Mine is cable tied doubled over to,stop water crossing ingress. I cut the tie and drain it every so often.

Hello.

Thanks for your response!

The oil is comming out from the gasket and bolt holes, the only vent hole that I have checked is the one of the left part of the engine that is pointing to the front of the bike and has a tube to the bottom of the motor with any restriction (the one that has the number 18 in the attached picture).

Where does that hole go? Because in the chamber of the power valve I cant see any hole... Can I loosen that nipple to check if it the hole is locked?

The vent hose of the pic that you send me seems to be in the right side of the engine and I didnt check it, it can be stuck?

Thanks!

Thanks for your response!

That vent hole is the one that I say in my previous message picture? The one with the 18 number and red arrow? I have that tube without any restriction, maybe is stuck in the inside?

Yes the tube and the nipple can get clogged

Yup both should be clear

Hello!

I have checked both vent tubes and the one of the right side (the nipple that points upwards) was completely clogged, so clogged that when I was cleaning it broke in half... I have bought a new one and I will test the bike but I hope that with that vent nipple unclogged and a new gasket the bike will stop ruining my shoes :D:D

As far as I have seen, at least in my engine model (ec250 2001) the left side vent is only for gearbox oil, and the right side one is for the powervalve so I think that the black spooge of the left side powervalve cover does not get out.

So thanks for your help!

The right side nipple is for the transmission vent. Left power valve vent.
Be aware that the two nipples have different orfice sizes.
Bigger orfice one is for the trans vent.

Hello, I had checked in the 2003 gas gas partlist pdf and both nipples had the same code "ME25710012", when it arrived to home I saw that the vent hole of the nipple is much more tinny that the one that the bike had, before mounting it I will probably make the hole bigger with a drill.

If something goes wrong I have 2 units.

Thanks for your info!