[davidpaul]

I haven't touched her yet but had an idea of putting some clear hose on the oil cooler line to see what the flow is like and whether air is being introduced into the system by oil starvation at the pump/oil pick up

[NMKawierider]

I haven't touched her yet but had an idea of putting some clear hose on the oil cooler line to see what the flow is like and whether air is being introduced into the system by oil starvation at the pump/oil pick up

Normally I would say pressure may be a problem with clear line but in your case..probably not...

[davidpaul]

Well ! after looking at the Z8 for weeks trying to gain the enthusiasm to investigate the fluctuating oil pressure problem,  I thought I've tried different oils but they've all been 10w40 or 20w50 mineral, part or full synthetic, so I had an idea of trying something different, tonight I warmed her up (still with 20w 50 in her) at full temp on idle and oil light was still flashing.
Drained the oil and refilled with Castrol Power 1, 4T Motorcycle 4 Stroke, Semi-Synthetic Engine Oil 10W/30, warmed her up again to full temp, and then 3 minutes on idle and no flashing oil light.

I haven't yet put the gauge on to see if the problem has completely gone, but feeling much happier

[NMKawierider]

That is so strange...but I use a Castrol product- Power RS or Power-1 10/40 T4 full synthetic.

[davidpaul]

If i have time tomorrow i will fit the gauge so i can see if it's cured the surging completely 

[davidpaul]

Fitted my gauge, when warming up oil pressure still varies but not so much but when hot on idle the needle is stationary at 10psi at 2500rpm she's at 22psi and only moving the width of the needle, at higher rpm she gets to 40psi and the needle is varying a lot again, return to idle and she's still on 10psi again.

So the 10w 30 oil has made a great improvement but not cured the problem completely, i have read that some engines can hold oil in odd places creating oil pressure surging as the oil does not return to the sump fast enough.

Is this problem common in other cf moto engines and leading to their early demise

My next test is going to be filling the sump with another 1/2L of oil and see what that does to the high speed surging

Adding the extra oil seems to have raised the point the surging starts to about 4000rpm, so i have a steady needle from idle to about 4000rpm

[davidpaul]

I've just noticed something, although the oil pressure switch has been removed the oil light still works as if it was connected, turn on the ignition switch and the oil light comes on start the engine and the light goes off ?

[NMKawierider]

I've just noticed something, although the oil pressure switch has been removed the oil light still works as if it was connected, turn on the ignition switch and the oil light comes on start the engine and the light goes off ?

So..even though it isn't even installed or even have it's wire on it, it acts like it is? The light shouldn't go off..no pressure to open the switch..oh but wait..with it not having a ground it would go off. Still..weird the light is on with just the key on.

[doug80638]

These symptoms are confusing and I don't know if this will help or not, but what the heck.

Given what's been offered about the low oil pressure, the gage test running at the spec minimums (or less) and does better with thinner oil, I would check both the oil strainer and the pressure regulator valve, if for no other reason than to eliminate them as contributing factors. Double check the filter and filter housing ports for good measure.

The low oil pressure indicator illuminating when the circuit is not grounded through the pressure switch sounds like a short. Was the connector leaning on the engine/frame?

 
 

[ctdls]

Not that I'm feeling bitter, but ahhhh, just put in some 20w50 and the oil pressure is still dropping to zero and back up again, I'm seriously thinking about selling her/it as spares or repair.
If it is the relief valve and as there's room around the valve should I be thinking of adapting one say out of a descent motor bike ?

I'm guessing there might be some background to a post like this? I tried reading the thread & thought.........Huh?

So I'm throwing this out to see if it is significant.

From 2015 model year, CFMOTO has made changes in the internal distribution of the engine oil on the V 2
800 cc engines. Among these changes, the in and out engine oil hoses for the oil cooler were relocated at the
crankcase. This relocation has necessitated the addition of a one-way valve incorporated in the oil outlet
banjo bolt that is located above the oil filter housing.
In the event you were to remove the banjo bolts inlet and outlet, make sure you reinstall them in the right
place If the banjo bolts were reversed, this would prevent oil to flow freely
which could damage the bearings of the crankshaft due to lack of oil pressure.

[davidpaul]

Thanks guys, I rebuilt the engine 1000miles ago after suffering big/bottom end bearing failure, weather this problem caused that fail i don't know, anyway tonight i have put an extra 1L of oil in so now she has 4L in her and it's the best reading I've had, nearly none or very little needle movement. she reads about 10-12 psi on idle and now goes to 50-60 psi at 5000rpm.
Looking at pictures of crankcases i can see what would hold back the flow of oil to the oil pump, 2 things i have thought about is the gear box when in motion pulling the oil away from the pump and the other is the actual oil pick up seems quite large for a small pump, one more thing is the pick up isn't lower than the main part of the sump so there's more room for the oil to spread out.
Just my findings and thoughts, as many owners have had engine failures i do wonder if this is the cause.

[NMKawierider]

Hmm..I think I'll continue to run mine a little overfilled...

[doug80638]

"put an extra 1L of oil in so now she has 4L in her
"

How did you keep the oil from running out? Tilt the buggy?

[davidpaul]

I removed the rear rocker cover and filled from there, I may get the extended filler tube and dip stick and modify that to the new level

[Hrc630]

Wow, 1 liter more is a LOT of  oil...
Keep an eye on your seal...
Also check your airbox.

500 ml can be ok but 1 liter is way to much oil in my opinion.