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Oil pressure questions

14K views 60 replies 6 participants last post by  Brader 
#1 ·
I've run another thread on this, but wanted to make one discussing just the oil pump, and the lubrication system. thoughts relating to this subject are welcome:wink

The symptoms i have been experiencing are not following a pattern i am familiar with.

Having looked at the parts diagrams, I now realize the pump itself is not the diaphragm type I am most familiar with. It looks to be a meshed impeller design, similar to a supercharger in operation.

I would expect this to be mechanically reliable.... More so than a piston style would be.

Because the design is different, I am unfamiliar with its characteristic behavior.

Every oiling system must use a pick up to gather the used oil from the lowest point in the pan, to recycle the oil. With the types i am familiar with, that's simply a pickup tied to the pump intake.

The zx seems to have a check valve in line? Filter at the bottom,a tube, gasket, valve, then it appears to go to the pump intake? All of that is inside the oil pan...... No point in opening that up if the pump itself is going bad (pump is externally accessible).

Because the low pressure light only comes on at normal idle speed, with the engine fully warmed up, and seems to do so only when it's in gear with the clutch disengaged (lever pulled in)...... I really wonder what's wrong.

If I had to describe the problem, it would be weak pressure, at low rpm, with thin oil. Just doesn't seem to point at a pump which can deliver 'high' pressure, with thick oil........

My guess at this point is the check valve in the pickup tube from the pan. I'm guessing that acts like a float bowl for a carb..... Holds a 'prime' for the pump. If the oil leaks back, the pump would starve in low demand as it would not be pulling a lot of oil from the pan. It would start 'dry'.

I think if the filter in the pan were clogged, I would have more problems with more demand. The light should come on more, with higher rpm.

My other suspect would be the bypass valve in the filter. If it's stuck open, the oil would not be routed where it should...... Does that sound right?

Third highest is the pump itself.......

A distant fourth is the oil pressure sending unit.
 
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#2 ·
If you really want to get a handle on what is actually happening. A true pressure reading is a must.
Pull the oil sender, put a male stand off with a T fitting. One to sender other to gauge.

Real time readings instead of an idiot light.

Your spot on about check valve, stops loosing prime to pump. Could see having issues with a long delay in light going out.

Your symptoms are odd, when was the oil changed last with what weight, and of course to the proper level. Also what rpm does the light come on.
As in does the bike being in gear at idle drop the idle lower than while in neutral?
 
#3 ·
You might be surprised just how much of an oil pressure swing there really is.\\


cold start up and high idle can surpass 60psi while once fully up to temp and hot and low idle you can see sub 10psi

If memory serves correctly I think the standard is @ full operating temp (approximately 195* oil temp) and 4000rpm to be 20psi +/-


You may be surprised how fast pressure falls off as the impellers (inner/outer) show some scoring and the gap between body and the rotor wears.........and even the oil pressure bypass spring gets weaker with use and age and can lower pressure (it is partially open most the time, and wide open some of the time)


I would hardly call the pick up screen a "filter"..... it simply keeps the really big stuff from getting sucked up- if it does not tear first, as they often do



But I thought you had found a loose wire and got this idiot light sorted out????
 
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#4 ·
The loose wire for me down to only getting the light at idle, in gear,with the clutch disengaged...... It will now consistently light in that configuration when the engine is at full operating temp.

Just to eliminate the possibility, I may swap out the pressure sensor so I can concentrate on the higher complexity options. Tearing the pump down and THEN finding it was the sensor would be annoying.....
 
#5 ·
Add the gauge before replacing the sensor.

Nice new sensor and it still does it proves the old sensor was OK but give no indication of how low or bad your problem is.



With a gauge you will learn what pressure makes your oil sender and what trips it. How new oil effects your symptoms.

Lastly if you do anther pump what pressure you should have been running.

Once fixed, remove gauge if you wan't.
 
#6 ·
I am a great believer in data based decision making..... Knowing the range of pressure I need to measure would allow me to buy a gauge to do that.

This is similar to what people think when messing around with electrical issues.... Anybody know what the size and thread is on the sensor port on my '09?
 
#7 · (Edited)
Every Kawasaki made for more than a couple decades has required the same tool

57001-1278................. (when I bought mine in the early 80's it was under $10.................may still just be worth it to buy the oil adaptor tool!!! rather than trying to cobble something together or waste days trying to find something)

but the inserted part is (best guess here on diameter) ............. 17x1.50 and the outlet side going to the gauge is 13x1.50 ??????????? hand measured diameter.....so best guess.............pitch is correct though

that is just the adaptor..............you still need an oil pressure gauge, and a range from 0 to 60 should suffice for this but 0-100 would cover about everybike possible (disregard the top and bottom 10% of range as less than accurate on most)

 
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#26 ·
Lloyd,

I'm prodding along on getting myself an adapter so I can use the gauge I bought.....even if the problem is resolved, like you said it's best to have the tool on hand.

I've asked one of the parts houses if they have it in stock. If they do I will buy that and bodge together from there. The parts listing on the same site calls out the plug as 25 X 8.... I'd expect that to refer to the dimensions in mm, right? M25, 8 mm deep? This seems quite large compared to what you were saying above.
 
#8 · (Edited)
Thanks, Lloyd.... that's the sort of info that comes from long experience. I had noticed that when I looked in filter catalogs that every Kawasaki seemed to use the exact same model filter. Hadn't taken that any further to check anything else that would be common over decades.

FWIW, during my training in electronics when discussing any type of analog gauge I was told that the accuracy was best, in the range it was meant to measure, which was center sweep.... the decreasing accuracy meant that anything outside of the center third of the sweep was less accurate and approached ridiculous at the extreme ends. My bench mark was taught to me as
'center third'.
 
#9 ·
This should do the trick, right?

I swung by an auto parts store to see if they had a kit on hand, and they offered to let me use their loaner...... provided I gave them a $150(!) deposit...... the Harbor Freight unit at less than $25 seems like it will be good enough to provide me the info I need. If it works once, and I toss it, that's still worthwhile.
 
#10 ·
maybe??

I have no idea what adaptors come with it nor how accurate the gauge itself really is............ no doubt it is automotive based not powersports based- so it may or may not have one to fit your bike..............
@ $22, may be worth the shot though
 
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#14 ·
Check oil level too. Too much oil causes the crankshaft to slap the oil and aerate the oil causing low pressure. Kawasaki oil filter? Correct oil? Oil level? And check for correct Idle speed. If all good check to see what actual oil pressure is there by workshop gauge.
 
#15 ·
Also, a few guys have reported similar oil pressure drops when changing from semi synthetic to full synthetic. Motul 5100 is what my Kawasaki dealer recommends. It is semi synthetic 10w40. A few people reported low pressure at low revs.
Once above 2000rpm the oil pressure returns, but under that the synthetic sometimes causes issues.
When you select a gear and pull the clutch lever you increase drag from the gearbox, clutch and drivetrain. This causes the Idle speed to drop slightly.
 
#16 ·
^^ The timing of the issue coincides with my first use of Mobil 1; I have a hard time believing that it would be so different from blends, or conventional oil of the same grade as to become so thin with heat that it no long acts like those other oils do. It's marked as 10w-40, when at operating temp it is supposed to flow and provide the same protection as conventional single grade 40 weight oil.

I don't think the oil is the culprit. Especially when the problem persisted after changing to conventional oil.

I'd prefer that the problem were the pressure sensor, but recognize that it could be a check valve, the filter, or the pump itself.

I should have time to get more data in the next few days. I've taken vacation time over the next 4 day work week.... As soon as my wife quits adding to the Honey-do list, I'll get to it.?

Somehow, cleaning horse stalls for a neighbor has been put on that list. Can't really complain, the boyfriend in that couple has hauled my brush hog to his shop and took care of a mechanical problem at no charge I didn't have the tools to deal with.... I owe him, so I'll help her. My son and I will deal with it over a couple of days. Four stalls about 14 x 14, at least 10" deep in filth. ..... She hasn't asked us to clean them out in more than 6 months.... They could be worse yet than I expect.

Once I have recovered, crawling around on the garage floor is going to be a pleasure.
 
#17 · (Edited)
Since I had a new Fram 6017A filter on hand, it made sense to swap that out first and bring the bike to full temp..... A balancing act, as I have the fairings off, which disconnects the charging system. No lights except the LED tail light, just the instrument panel, and the ECU pulling juice from the battery.

I let the bike run for about 10 minutes, without seeing that low pressure light. The coolant temperature got to 200F, I put the bike in first gear multiple times, slipped the clutch to slow the engine to ~1K....... No pressure warning. I'll put it on the charger to replenish the battery, and will likely repeat the experiment.

Lloyd, the plug for the pressure measurement looks like it's adjacent to the port for the pressure sensor. Less than an inch away, looks like it's the same channel in the casting? I previously thought I had to pull the sensor, and use that point for the gauge?..................... nevermind, I found the reference in the shop manual. That's it.

I should be able to pull that plug and match the kit's adapters up to that, then have it all set up to check the bike. Seems like that should be something I can do with the fairings on the bike, given the location of the inspection port.
 
#19 ·
I've been running Frams on this bike since I got it with 12K miles on it, and it now sits North of 52K. I'm happy enough with the Fram to keep running it, provided nothing has changed in the materials used to mfg it. If this has cleared up the remaining issue, I would suspect that the full synth knocked dirt loose in the motor, which caused the filter to get more clogged than my typical level.

Miles will tell the tale.
 
#21 ·
..... STILL not sorted out. Started the bike ride out the gate three miles to the first stop sign. No light, until I got to that stop sign. The light went on, I couldn't get it to go out for the few seconds it took to start out again. I hammered the gas launching from the line.

The light went out. I had to go about a mile before I could get turned around to head for the barn...... The light stayed out. I rode back past my house, out into the countryside.... Light stayed out. Temps on the motor were good, no problems with power, no noises or smells.... Decided to run it a little further.

10 miles later, the low fuel light comes on, nearest has station is another 10 miles..... Still, no light. Stopped and filled the tank. No light when I started it up. Now, I'm 20+ miles from home --- I could go back the way I came, or make a loop on big enough roads that My wife should be able to find me on, if something happens. Great circle, it is.

All told, another trip nearly equal to my normal commute. Same symptoms.

I really need to get an adapter and make the measurement.... Or bite the bullet and rebuild the oil pump.
 
#24 ·
yes, but you still have to check pressure and make sure it isn't just your switch or wiring or instrument cluster light etc.....
there are other possibilities beside the pump and I do not like just throwing parts at something without knowing or atleast be mostly certain...
but the rotor pair is cheap and so are the o-rings, it can't hurt to do them, but it may not help......... I routinely see about a 4-6psi drop in oil pressure from freshly built engines to worn enough to tear down and rebuild--this won't equate to a low pressure warning light

Some loss comes as the bearings wear (crank and rod bearings), some as the bypass spring softens, some as the pump rotors score and wear, some as that housing wears

By all accounts of what you describe you aren't actually losing pressure or you would have had some catastrophic failures by now I think.....
 
#27 ·
No way is it 25mm diameter............. I don't care how you measure the threads or hole it just isn't....

57001-1278

Just order the oe part and be done with it............ super cheap really when you consider how much time and effort you are going to waste trying to get one elsewhere
ottherwise pull the port plug out and take that in and match it up???

 
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#28 ·
I agree on every point, Lloyd. Thanks for the P/N. My nearest Kawasaki dealer is >30 miles from where I sit. When I have a chance on Tuesday, I will go there and see if they have one for sale, as it is much closer to where I work than where I live.

I took the bike out for two hours yesterday. No lights, right up to the last 6 miles(!). Couldn't believe it. I rode, and rode hard for well over 100 miles at 6-13K, sustained speeds for many minutes at a time that would have landed me in jail in a more built up area...... coming through the last town on the way home, stopped at a traffic light, and the oil pressure light came on.

Popped it into neutral, stayed on. Pulled to the side of the road, blipped the throttle, stayed on, went out and started blinking off and on with no rhyme or reason. I elected to ride home, at which point the low fuel light lit as well. Stopped at a station and filled up. No oil pressure light, when I started it back up. Rode the three miles to the house, and it stayed off on the 500' driveway, then lit again when I got it to the garage.

Still no indication of a fault, other than that damn light. I promise, I will have the parts to make the gauge work before I do anything else.
 
#30 ·
The Kawi adapter is in my possession, and my oil pressure gauge kit did not have an adapter to fit to the output side of the Kawi part.

For anyone's future reference, that output side is male 1/4" NPT. I found a brass female-female 1/4" NPT, which I DO have an adapter for.....should be able to get an oil pressure reading later today, or tomorrow.

As Lloyd pointed out, this has been something of a cluster f*ck, to get everything to mate up.

I can't think that I could have done this any easier than by having the Kawi adapter -- it might have been simpler after that to have a gauge that plugged right into that.

So far I've spent $28 for the adapter, less than $30 for the oil pressure gauge/kit, and another $3 for the female-female 1/4" NPT. If that allows me to buy one part instead of purchasing another $200 worth playing parts roulette, it's still money well spent.
 
#32 ·
To rub a little more salt in the wound, the price for the correct adapter ( 57001-1233) ordered through Partzilla was less than $7. Compared to the $28 the closest Kawasaki dealer was willing to order the other one for........ Having dealt with these mercenary so and so's before, I should have figured they would rake me. Add in the toll to go over the bridge and the additional 30 miles of driving -- I now remember why I started doing all my own work on this bike.

I placed a Partzilla order instead. The right adapter, along with a new pressure switch, a new bypass valve, and the gaskets needed to install the valve. Including 1-3 day shipping I spent <$60 and will likely have extra parts when I am done. Since we had a flurry of snow today, I don't feel as bad about this as I did when it was sunny and getting warmer.
 
#33 ·
Parts arrived today... Installed the new pressure switch first, being careful to not overtourque it, discovered I had splayed the forked contact, fixed that and made the connection. Started the bike and the low pressure warning went out as expected. +1.

Then, I built up and mounted my pressure gauge with the correct adapter. Started the bike cold with indicated ~20lbs @idle, ~60 @4K RPM. Not great numbers, I'll need to check the shop manual for the right values; could be the cheap gauge, or the pump is weak, or the relief valve is stuck. Or it could be acceptable as is.

Shut it down and cleaned up. Spent some time trying to figure out an install that would let me ride with that pressure gauge installed on the maintenance port...... Seems to extend too far past the block for my taste, with all of the adapters I had to stack.

If I can buy an electronic sending unit and display pressure near the instrument cluster, I'll be all over that. I'd like to see warm pressure numbers, and run the thing for another 1,000 miles without issues before I close this out.
 
#34 ·
Was this cold?

20psi @ idle cold and 60psi revved up some cold oil................. if so, that sounds like normal operating

ideal would have been check it with oil temp at about 175*
 
#35 ·
That's good news, yes, the motor was completely cold, room temp <40 F.

I should have time tonight to let it come up to temp, and check again.

What water temp would indicate oil temp should be at or near 175? Am I correct in thinking the water warms faster than the oil?
 
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