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Don't add more oil if you already put in 3.5 liters. Normally folks fill the oil filter before installing it.
Unless you live in the desert, you shouldn't be running 20-50w oil.
Manual clearly specifies 10w40.

When you say it's overheating, how far into the red is the needle moving?

I think before splitting the cases I'd make sure the oil isn't getting pumped as Birga suggests. You then should try putting some SeaFoam in the oil and running the motor a bit to see if it clears up the flow.

Are we sure the water pump is working properly? As I mentioned this would effect engine temperature much more drastically than the oil pump.
 

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Discussion Starter #22 (Edited)
Hang on, your oil light turns off when the engine is running, but you get no oil out where the filter screws on if you remove it? I mean, the pump must have been moving SOME oil when you overheated the first time, since the oil sight was reading empty. Even at 7-8 PSI there should be some movement. Just saying the symptoms don't necessarily add up. On the other hand, these other guys are right more often than I am!

The oil light doesn't turn off, it stays on. And I'll check the external lines this evening when I get home. I tried burping it yesterday evening hoping there was an air pocket and almost no oil came out.

KM the engine had no knock prior to the overheat. When I say overheat I mean that the needle was increasing past the thermometer and was at the red line, not into the red zone, when I pulled over. My concern at this point is the engine noises. I dont see any oil leaving the sight glass, even while running
 

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The oil light doesn't turn off, it stays on.
Ok, I thought you previously said the light went off after it was running. I may have misunderstood.

It could be the chain for the oil pump drive has broken. That's known to happen.

Not sure I would try running seafoam, if it has no oil pressure, you're just doing more damage. If it's not pumping out of the oil filter, it's not pumping anywhere.
 

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Discussion Starter #24
Don't add more oil if you already put in 3.5 liters. Normally folks fill the oil filter before installing it.
Unless you live in the desert, you shouldn't be running 20-50w oil.
Manual clearly specifies 10w40.

When you say it's overheating, how far into the red is the needle moving?

I think before splitting the cases I'd make sure the oil isn't getting pumped as Birga suggests. You then should try putting some SeaFoam in the oil and running the motor a bit to see if it clears up the flow.

Are we sure the water pump is working properly? As I mentioned this would effect engine temperature much more drastically than the oil pump.
As far as the oil weight, I used 20w-50 Mobil1 for V-twins. I thought I read in another post that this was an acceptable weight? As far as the water pump, unsure but I'm sure I'll find out when do the tear down to see whats wrong.
 

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Yup, time for a teardown. Sorry to hear it.

The timeline of the whole thing is fairly mysterious though. Oil pump was obviously working when you pulled over, then failed immediately afterwards. I'd be interested to know what happened when you open it up.
 

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There's some chance the problem could be the pressure relief valve. A longshot, but still some chance.

The oil light switch threads into the relief valve, which is threaded into the engine block.

The manual states to check the valve by pressing on the internal check ball and see if it moves freely and springs back into place when released.

If the relief valve happens to be stuck open, oil pressure is lost.

Here's a pic of the oil switch and the relief valve: ... pic won't post, so here's the link: https://www.google.com/imgres?imgurl=http://i40.tinypic.com/2nb56qo.jpg&imgrefurl=https://www.vn750.com/forum/29-equipment/38786-oil-pressure-gauge-pro-con-2.html&docid=9NwZIVucHgGpYM&tbnid=T6R4X8uEZkubNM:&vet=10ahUKEwi6qofN-drjAhUbHM0KHa9uB-EQMwhJKAYwBg..i&w=640&h=480&itg=1&client=firefox-b-1-d&bih=491&biw=1013&q=vn750 oil pressure relief valve&ved=0ahUKEwi6qofN-drjAhUbHM0KHa9uB-EQMwhJKAYwBg&iact=mrc&uact=8

 

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The check ball is inside the part with the long threads.
 

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Looks like that's just a pass-through, not a relief valve. Maybe some years are different on that detail.

Here's a shot of a vn750 valve with the ball. Looks like it would just vent out the side onto the ground in an over-pressure situation, or if the ball were stuck. You'd be losing oil out the side if this part were the problem (unless there's a blockage in the tubing).

https://www.partzilla.com/product/kawasaki/16130-1001?ref=f02b8ecc63bd7c9bf7ee10b9d48e6c055e024b01

Mine is the same as yours, with no side hole.

EDIT - The Haynes manual lists that part as 'switch fitting/union bolt', and shows no hole.
 

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Discussion Starter #31 (Edited)
Looks like that's just a pass-through, not a relief valve. Maybe some years are different on that detail.

Here's a shot of a vn750 valve with the ball. Looks like it would just vent out the side onto the ground in an over-pressure situation, or if the ball were stuck.

Mine is the same as yours, with no side hole.
So what does this mean, it's the oil pump right? Because nothing should be stopping it from building up pressure.
 

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So what does this mean, it's the oil pump right? Because nothing should be stopping it from building up pressure.
Yup. Since your oil light stays on it looks like either the pump is shot, the chain is broken, or the pump intake is clogged.
 

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Man, I'm sorry, I screwed up. That relief valve is under the stator cover. I got it mixed up when I looked it up earlier. I must've been hurrying to get out of this chair, back has been really bad the past week.

Crank it over several times with the oil switch removed, see what you get.

Hate that you spent time checking the wrong place because of my screw-up. :doh:

It's in 6-12 of this manual. http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Either way it looks bad, because the relief valve is under the stator cover, and oil pump is deep on the clutch side.

Seems I recall someone replacing the oil pump chain just by removing the clutch case, but to get the oil pump out, the manual says to "remove the crank".
 

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The first time I rode my 95 Vulcan 750 after buying......(2003)....,
I had thought oil was too low so I filled it to upper line while engine was cold.
Bad idea.

12 miles later oil was sputtering out of both my air filter ears.

I drained oil down (perhaps a quart)
I had supplies).... cleaned up the mess.... cleaned everything mostly with carburetor cleaner, and refilled to correct level. I never had a problem again. That was 16 yrs ago.






So a weird thing happened today. My bike started to overheat on my way to work. I pull over look at the sight glass. Low oil. I think to myself well shucks. Put oil in it, start it up, sounds good. I get on the interstate ride a few miles, I see the temp gauge start to rise. I feel warm fluid hitting my right leg and see oil coming out of the right air pod.
This leads me to pull over and call for a tow. I'm on the side of the I81 south now waiting, I cant help but wonder WTF happened. Did it get over filled with oil and backflow out through the air intake? Did I seriously f*** up my bike? What happened internet? Any insight would be great.

Ps there were quite a few motorcyclist that stopped by to check on me and gave me some water along with 2 state troopers. Shout out to the great people of the universe.
-the newb Firstbike
 
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