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Return oil pump screen flush?

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Thanks to all who have been here before me!


First Time Post lots of awesome info out here! I'm looking for a quick fix. I've been running through this bike for the past year putting hours of time into it. (Common). Finally got it dialed! But like they say. "Just when you think you've got it all figured out... your wrong!" Topped off the oil. Checked it. All good. Went for a ride. (1hr.) checked the oil. No reading. Topped off. Checked oil. All good. Went for the same loop. No reading after ride. WTF! Did some research. Frame oil screen clog. Checked and cleaned. No love. Did some more research. oil pickup screen in lower or oil pump culprit. Noooo!

Crankcase oil dark.

Frame oil clear.



No guaranties expected.

Is there an effective way to flush the pickup screen without splitting the case?

I have been up and down this bike and it runs great outside of this oil reading/flow problem.

No smoke

No engine seize

Seems like restricted flowed oil to frame





01 DRZ400S,



06 forks, shock, top end, for 39(165 main, 48 pilot, sea level), Ricky stator, e air box, plastic tank modified fuel on off, rev max cdi, wiseco cam chain, wiseco valves, wiseco clutch kit, race tech coils front & rear (200 lb), moose bars, adjustable levers, trailtech computer. Etc.




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You are going to have to help me out here.  You are putting oil in but it keeps indicating low on the dip tick.  Where is the oil going?  Do you have reasion to believe it is staying in the sump and not returning the oil tank?  If you remove the oil filler cap with the motor running you should be able to see the oil retuning to the tank.  It is kind of fits and spurts because the return pump is twice the volume of the feed pump. 

I'm not sure how effective it is but if you remove the oil pump you can flush back flush the oil pick-up screen.

Have you drained the engine sump and found an excessive amount of oil?

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Thanks for responding!
3 liters have been put in the bike.
1300ml too much
To clarify. I fill to good reading and bring the bike to temp. Check the oil and it reads ok. Then I go for a 1 hr loop and check oil again at running temp. No oil on dipstick. Then I topped off with almost another liter and bring back to temp. Take another reading and it looked ok. Then I rode another 1 hr loop. I checked the oil when I return. No unification on dipstick.
It seems that the oil is holding in the sump.
I drained the left case and most of the oil came out of that plug. (Almost 2+ liters)
Then I drained the frame before the frame screen and the oil in the frame looked brand new( not cycled) (about 1 liter)

The frame screen was not that dirty either
I will check the filler cap while running but I'm pretty positive it is not picking up on the return pump. Or the screen is clogged.
I will pop the right cover as soon as I get a chance , remove the pump and try flushing.
What do you think would be the best fluid to flush the screen with?
I'm thinking diesel

Thanks again for the insight Noble!!
Sorry if my post are long winded.
Just trying to show the process I've been through.

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The only oil that gets circulated by the oil feed pump comes from the frame.  If as you say the oil in the frame looks new I have to wonder how the motor is being lubricated. The residual oil in the motor does nothing.  I suppose if there is 2 L in there it must be sloshing around and maybe doing some lubrication but the top end would be pretty dry I would think.

When you remove the right side primary cover you will be able to see the gear train that drives the oil pump.  The intermediate gear is reinforced plastic.  I wonder if it is broken.  Worth a look.  Yes diesel to flush.

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As far as I can tell, oil is moving out of the frame. I am assuming it looks new because of the lack of oil returning to the frame.
I replaced the cam chain about ten hours ago on the bike and the plastic gear was in good shape. I am aware of its tendency to fail and I'll definitely check it out.
I also replaced the valves less than ten hours ago. During the shimming process I could tell that oil was being pumped up to the cams.
My plan is basically to flush the pickup screen (a few times) and If necessary, order a new oil pump assembly and plastic gear.
Just got to find the time and order the parts.....
And hopefully I won't have to split the case.... ??
I'll let you know what I find as soon as I can.
Thanks again!

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So here is what I found!
Oil pump idler gear missing two teeth.
I back flushed the pickup screen and there seems to be no resistance.
The first couple pumps shot back at me then it seemed to flow smoothly
I tested the oil pump with a drill in water and it worked both ways.
When I ran the pump backwards, there were leaks in the seam of the pump housing, but I'm assuming that once it's mounted back to the motor, the mounting screws will hold it tight.
Or is that a problem?
Then I blew air through all three holes where the pump mounts and got good air flow.
I checked my oil filter(not very dirty) and replaced it.

In conclusion I hope the back flush worked, and I have a new oil idler gear on order.
I'm on the fence whether i should pick up a new oil pump or not.
What do you think?
Am I overlooking anything?

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When crap goes thru the oil pump it puts extra strain the the drive gear.  So possibly that or the clutch was put on some time when the gears were not lined up.  I recall you had the clutch out, right?  Inspect the oil pump and if you don't find problems where the pump rotors mesh together, it should be fine. Not such a good idea to pump water, the oil pump likes lubrication.

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I only had the fibers and plates out. Must have been the previous owner.

I have reinstalled oil pump, new idler, gear, clutch(checking that the idler gear is engaged), side cover, oil filter, oil, and coolant.
It took a full 2 liters.
As the bike was running, I looked in the oil filler plug for the random spurts of oil aaand... nothing! [emoji848]
Then I started raving the bike to try to build pressure on the return line aaand...
I could see th oil being drawn into the bike and being spit back into the frame!
Of course I had to take her for a little spin and she's keeping her levels up!
Thanks again for all of your insight on this fix! Really helped keep me in the right direction!
Hopefully someone else can use this info in the future for a fix.
Pickup screen flush worked for me!!![emoji106]

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