1950 Airone Oil pump spring

[John Martorano]

Hi All,

Could anyone tell me the specifics about an Airone oil pump spring or where I can get one.

Thanks, John

[vanuss...@gmail.com]

I don't see a spring in the oil pump? The pressure on the return vanes is regulated by the thickness of the packing.

Or are You looking at the   pressure valve?

Op zaterdag 15 november 2025 om 19:17:17 UTC+1 schreef John Martorano:

[Patrick Hayes]

On 11/15/25 10:17, John Martorano wrote:
> Could anyone tell me the specifics about an Airone oil pump spring or
> where I can get one.

Careful. I presume you are asking about the automatic valve to control
oil drainage when the engine is stopped. That spring tension is
critical. Too loose and you risk wet sump. Too strong and you risk
restricted oil flow at lower rpms. If necessary you could abandon that
valve and use an external manual valve. The automatic valve was
intended for bikes ridden every day. Not a perfect seal. Wet sump
isn't an issue if you ride every day to move oil back to the supply
tank. Sit for a month and then you have a problem.


--
Patrick Hayes
Fremont CA
Falcone-NT and SuperAlce
www.motohayes.com

[John Martorano]

Hi Patrick,

Thanks for responding. I am referring to the oil pump, but it’s been 10 years since I removed its cap so Im probably mistaken about pump having a spring between the opposing metal pieces.  Could you confirm that for me please? 

Concerning the automatic, I won’t ride the bike often.  Is there something I should do?

Thanks, John

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[Patrick Hayes]

On 11/15/25 10:17, John Martorano wrote:

> Could anyone tell me the specifics about an Airone oil pump spring or
> where I can get one.

John: There are TWO springs inside the oil pump of a Guzzi single.

The first is located between the two vanes of the scavenger or oil
return pump. This spring keeps the two vanes pressed outward and sealed
against the outer wall of the housing.

The second is located around the stem of the automatic shut-off valve.
When the engine stops, oil could still gravity drain down past the oil
pump gears and collect in the sump. Makes for a lot of smoke and mess
on the next startup. The valve is closed and sealed by this spring and
oil is prevented from draining down. It is NOT a perfect sealing
system. Works fine for bikes used regularly. For those only used a
few times per year, it may be practical to install an external manual
oil supply valve. Just don't forget to turn it on before your next start!!!

Do you have an explosion manual for Airone Parts?? Please refer to the
diagrams on the page with the oil tank and various oil supply lines.
Perhaps Tavola 6? Thereon you will find explosion of the oil pump and
the presence of both springs.

I doubt there are any listed specifications for either spring. When in
doubt, source a new spring from Italy.

[John Martorano]

Thanks for the advice Patrick!

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[John Martorano]

Hi Patrick,

I received the oil pump spring from Italy, but it’s very difficult to install it because the spring needs to be completely compressed.  This doesn’t seem right. Is that the way it should be?  

Thanks,

John

[Patrick Hayes]

On 12/10/25 10:15, John Martorano wrote:
> I received the oil pump spring from Italy, but it’s very difficult to
> install it because the spring needs to be completely compressed.  This
> doesn’t seem right. Is that the way it should be?

Can't recall. Its been a long time since I had one disassembled.
Do you still have the old spring? Can you photo the two relaxed springs
side-by-side? Maybe someone else in this group has one apart currently.

[John Martorano]

I don’t have the old spring and my Airone oil pump has just one spring.

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[Patrick Hayes]

On 12/11/25 10:33, John Martorano wrote:
> I don’t have the old spring and my Airone oil pump has just one spring.

Maybe someone else has a shutoff valve taken apart and might post an
image of the spring. Perhaps share specifications of diameter, resting
length, number of coils?