Oil Pressure issue VF 1000f 1984

Hi Brains Trust, my 84 VF1000F oil light is flickering at idle (1100rpm) when the engine is hot, increase the idle to 1800rpm and the light goes out. When cold the light is off, was thinking I will need check the oil pickup , bypass valve and the pump. I did check the oil pressure with a gauge and found the best pressure I could get at 5000 rpm was 40 PSI, the low end of the spec in the book is 67 PSI ( 77± 10 )
Does any know if 40 PSI is ok to run?
Am I on the right track before I start pulling things apart?

Any info appreciated…Tony (Australia)

Best to drop the sump and check the pick up screen,you may simply have a clogged pickup

Thanks for the prompt reply Bif, in your experience have you heard of oil pressure at 40PSI?

With cold engine the oil is thicker, so pressure should be higher. The more rpm the higher the pressure. So it seems to be not an electrical problem, as you measured with external meter.

How much km / mls has the bike? I would agree to Bif, If it is not the sump you should be able to get the pump out for further inspection.


It has just had a refresh with new rings and bearings, however there was an incident when running in where the incorrectly tensioned oil/water bump drive can\me off with a small amount of the inside casing. Although this was repaired and oil changed, the oil pickup was not checked and as Bif has indicated may have partially blocked the intake screen.

I’ve seen the pressure in the 10s at tickover but 40 does seem low for 5k rpm.
From your last post I think you are on the right track with the pickup screen

Ok got the sump off and the screen was very dirty, I did this yes Ive found the issue, cleaned this all up and installed new oilfilter and oil. tested and …no joy no improvement on the 40 psi. I guess the oil pump will be the next go to?!


I would strip the bypass valve next Tony,something isn’t right

Hi Tony,
bypass pressure relief is the next logical step, as Bif suggests.
From there its worth also checking the oil gallery plug on the clutch side, down below starter clutch. If this wasn’t seated you may loose some pressure? a long shot…
While your working on it, would be ideal to check the pump, and ensure there’s no bad scoring of the pump plate, which could mean pump was not building pressure to spec?

oil pump
Took the pump apart, picture may not do it justice, but looks like slight scoring (you can easily feel it) all the rest of the pump measures up within spec of the book. The only other thing was that one of the orings in the transfer pump was twisted and not seating properly. The bypass valve seemed fine when disasembled.

Was going to try to get another pump, but of course all the ones available are in Europe and I’m in Australia

Will also see if there is an engineering shop that can machine the face plate.


Hi Tony,
you can always try the course valve lapping past on a piece of plate glass method. As you are only removing a few thou of material it should work. I was successful with one of my VF pumps which looked about the same.

oil pump

The before and after shots, 80, 120,1000 grit wet and dry paper on a sheet of 8mm glass.
pretty happy, just waiting for some original O-rings to trial the whole thing.

Wish me luck

The O Ring was probably the problem; they are critical in retaining pressure. The Space Shuttle exploded because of an O Ring.

Hey Tony, nice lapping job. Don’t need a machinist when you do a good job like that. I assume you checked with a feeler Guage for flatness, and all was well. oil ring would have been letting pressure escape even just a little, so your pressure should improve.
Cheers John

Well that was disappointing, new O rings, lapped the oil pump face ( as per previous posts), inspected as much I can see without disassembling the engine. and still the best i can get is 40-50 psi…seem to be grasping at straws now.

You have gone through almost everything I can think of Tony,the only other items that could drop oil pressure are the inner seal on the output shaft failing or excessive wear on main or big end bearings.
It’s tough but a deep dive into the motor looks to be inevitable mate

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Hi Tony, sorry to hear that you still have problems with oil pressure.
There are two Oil orifice points in the bottom end of the motor. If someone has had the motor apart or the left-hand side covers off and has not replaced one or both of the oil orifices (and their respective O rings), then that could cause a lower than normal oil pressure. I would also make sure that all O rings have been replaced when you did the oil pump. The oil orifice behind the left-hand cover at the top of the cover, should be easy to fix. The other inside the gearbox means you would have to strip the engine down. The manual and a parts book can tell you what is missing or not. You can download them from this forum. Is it possible that they lost the oil orifice when the left-hand side cover was removed and fixed?

Cheers John, Thanks for the feedback, I am assuming when you say left hand side you are looking at the bike front on? Yes, I have replaced all the oil pump Orings on all the pipes including the one on the side, see the attached vf1 photo, the Oring is number16. the other photo vf2 is all that I can find on the ‘Orifice’ (this is the one we have to split the case for) are you saying this one has an Oring as well? I can’t seem to see one on any of the parts diagrams I have access too.

Any info appreciated as I seem to have come up blank.

cheers Tony

Hi Tony,
Left hand side while sitting on the bike.
In the first diagram, you have circled the oil gallery cap and O-ring. If this is leaking it can also cause a drop in oil pressure. I didn’t mention it before because Speedy had already mentioned it. You have to remove the left crankcase cover and Water pump. At the rear of the crankcase on the top in the middle is a locating dowel pin, the oil control orifice and the o-ring. If you have a parts book look at the left crankcase cover etc.
In the 2nd diagram the orifice that you circled is the one that you have to split the cases for. I will try to send a copy of the parts page if I can figure out how.
If you don’t have a parts book, send me your personal E-Mail address and I can send you the diagrams that you need or the whole books if you like. I am in Adelaide so I can even post one to you. it will be easier for you to check these two places first before you start pulling the whole motor down.

oops! Should read “at the rear of the crankcase “cover” on the top in the middle.”