Help needed please

sparkplug · Oct 17, 2012

Hiya mates,

After searching through the threads related to pcv valves I couldn't find any explanation to my problem.

Just installed an XS650 PCV valve and when I started the engine oil pressure is 40PSI which seems normal to me.
Problem is I get no oil return to the oil tank and pressure drops down to 0PSI after a couple minutes...
What am I doing wrong there?

Any help will be much appreciated. :wink:

1up3down · Oct 17, 2012

first: take off, uninstall the new breather valve and then start the motor to verify oil return and all is well

second: is it possible you installed it, this is really dumb of me, in an oil line instead of the breather line?

OR, maybe you installed the valve backwards in the line, possible, been done before

drones76 · Oct 17, 2012

For reference:

sparkplug · Oct 17, 2012

It worked fine until now. Pump worked great and oil returned to the tank inmediately after the engine started.
I installed the valve in the engine breather line substituting the adaptor it had originally, using the same old lines, as I other people adviced on previous posts.

I'm really confused and scared of damaging the engine

acotrel · Oct 17, 2012

Without knowing what work you've recently done on the bike, it is difficult t o help. Is it possible that you've interchanged the oil feed line with the return line from the motor ? My own bike is non-standard, and if you forget what goes where you can manage to end up pressurising the crank with fresh air instead of oil. If the PCvalve has been installed back to front, you might be pressurising the motor, but you should still get oil returning to the tank.

1up3down · Oct 17, 2012

take the damn thing off, verify oil flow back to tank and leave it off until this problem gets thought through

sparkplug · Oct 17, 2012

Just took the valve off and restored everything as it was before. Oil flows great back into the tank as soon as I kick the engine.
Oil lines on mine are standard as shown on the diagram.
The little oil I got back into the tank came spitted from the PCvalve but none from the return line.

acotrel · Oct 17, 2012

'Oil flows great back into the tank as soon as I kick the engin '

From the breather to which the PCV has been fitted, or from the normal return line ? ?

sparkplug · Oct 17, 2012

Now I took the valve off oil comes through the oil return line.
As I said the bike goes well without the valve. It wetsumped before I must say, but nothing else...

daveparry · Oct 17, 2012

You must have got the lines mixed up somehow, there's no possible way that installing the valve in the breather line could affect the oil pressure or return, in fact you could remove the breather pipe completely and it wouldn't stop you getting oil pressure! Also a pcv valve is not going to have any effect on your wet sumping problem,

Dave.

swooshdave · Oct 17, 2012

You'd be surprised at how much pictures help.

grandpaul · Oct 17, 2012

In the standard crankcase, how much of a factor is typical internal pressure in pushing oil through the oil pump/path to the tank return line?

Could it be such that without the pumping pressure (new valve installed), the oil pump is actually too worn/weak to return the oil to the tank?

maylar · Oct 17, 2012

People have reported that adding the xs650 valve can have an effect on the rate of oil returning to the tank. I have witnessed this on my own bike. I can't check oil level until I've ridden a block or so - it won't return fast enough at idle to drain the sump. I have replaced my oil pump and only got a modest improvement.

It'd be great if the collective wisdom here could figure out why this happens.

I'm considering ditching the valve and going back to stock plumbing.

Bob Z. · Oct 17, 2012

Here's what I found when I wasn't getting oil back to the tank through the return hose. A blob of silicon sealant had blocked the pickup hole to the pump.

maylar · Oct 17, 2012

Well, I noticed the reduction in return flow after installing the breather valve but never considered that as a cause. So I bought a new oil pump ($$$) and as I said only got a small improvement. I'm sure I've read here in the forum that others have seen this phenomenon.

Help needed please

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