A10 oil pump test

[Swarfcut]

 Rex is on the money there. Just giving that barn find bike a good kick is a recipe for disaster. Even when left on the shelf these pumps lock up.

 To dismantle a seized pump without damage a little bit of heat makes it easy, the idle spindle usually falls out on a well worn pump, the gears require gentle persuasion to emerge.

 As a kid, I remember Dad negotiating on a Morris Oxford. The chromed hinges on the boot lid had "bubbles" where the Mazak castings were starting to crumble under the chrome. So the longevity in use was questionable back then, but for a manufacturer it ticked all the boxes, and to last this long was never considered. So it got used on our oil pumps.
 Wikipedia gives the story, reckon Mazak was the UK trade name.

 Swarfy.

[BagONails]

Pot metal hates moisture and will grow and crumble if left dry in air or in an engine with dirty oil, full of emulsified water, condensation etc.
If you are storing a pump for later use, strip and clean it, run fresh engine oil through it then leave in a jar under clean oil or at least in a zip lock sealed bag to keep moisture away and it will be fine.

[RichardL]

This won’t add anything to the expert testing advice already offered, but does provide a visual of what I believe to be the proper oil flow. I made this video (gulp!) 16 years ago.

https://youtu.be/SfJ2zigEbqo?si=hg1BMogGexPSySHZ

Richard L.

[Else]

Morning all.
Good news, it’s working nicely now. I removed the SRM nrv and took the ball, spring and seat out and refitted it. I now get a good flow of oil back to tank.
My only concern is wet sumping. What damage does it cause? The bike isn’t going to be used every day, or every week. Probably once or twice a month through the summer but will sit unused through the winter months.
It has a drain plug in the sump cover so I will check it before each ride. What should I expect to be a reasonable quantity of oil after leaving standing for a couple of weeks say?
Thanks in advance to all you gurus, I’d be lost without your help.
Else

[Swarfcut]

   On standing there is a natural tendency for oil in the tank to flow into the sump via the pump,  the timing bush and from there onto the big end bearings. The oil way branches to the PRV....(Pressure Relief Valve the big nut on the crankcase front).
 The anti- wet sumping valve is situated  between the pump and the timing bush. It is a simple spring loaded ball, which moves under oil pressure to open the oil way to the timing bush. It is supposed to "hold back the tide" when the engine is not running. Only accessible with the crankcases split
  This oil drain down can be minimal on a bike with a good pump and bearings, to the other end of the spectrum where the oil tank empties in a few days.

 Used every day a smokey start for a few moments is tolerable, but if irregular use is the norm, draining the sump before start up is the way to go. Too much oil in the sump will reveal every weak gasket and get complaints from the neighbours   due to the smokescreen.

 As a rule of thumb, checking the oil tank contents should be part of the start procedure, no oil...... It's in the sump. On starting the return should be strong and steady, as there is always some degree of drain down  reducing to a gulp as the sump clears. Good motors do this quickly, not so for the majority running less well fettled machines.

  Swarfy

[chaterlea25]

Else,

I removed the SRM nrv and took the ball, spring and seat out and refitted it. I now get a good flow of oil back to tank.

Please confirm what you have removed?
Was there a ball and spring behind the SRM oil pump?
What seat?
I hope you have not removed the PRV ball and spring

John

[Else]

I have a standard oil pump and there is just the 4 open ports behind it.
The SRM non return valve is in the feed pipe from the oil tank to the crank case to stop it wet sumping. When you take it apart there is a ball, spring and a removable seat that has an O ring around it.
Else

mod edit: renamed the nrv to save confusion

[chaterlea25]

Hi Else,
Jeez, you gave me a fright when i saw your last post.
The correct abbreviation for those is ASV
"Anti sumping valve"

I know that SRM would never sell or fit such
a horrible nasty POS
Even though they must have made a living repairing the damage caused by them 

If you had told us at the start there was one fitted , the instant response would have beet to bin it

John

[Else]

Hi Else,
Jeez, you gave me a fright when i saw your last post.
The correct abbreviation for those is ASV
"Anti sumping valve"

I know that SRM would never sell or fit such
a horrible nasty POS
Even though they must have made a living repairing the damage caused by them 

If you had told us at the start there was one fitted , the instant response would have beet to bin it

John

Thanks for the info John.

The ASV has SRM stamped on one side with an arrow to show direction of flow. I’ll attach a picture of it in situ. I will also attach a picture of the ball, spring and removable seat just for reference.
Hopefully I won’t get too much wet sumping as the pump is in relatively good condition so shouldn’t let too much oil seep through when standing.
Else

[Else]

SRM ASV in situ and the internals, ball, spring and removable seat (o ring removed).
Else

[Rocketthree]

Apologies for my previous post where I got completely muddled with tech terms. Here's what I should have said.....
Interesting...... A mate of mine had poor return to the tank. To cut a long story short, we ended up removing the SRM anti wet sump valve, problem solved! It seemed that the SRM anti wet sump valve was preventing some of the oil getting into the gallery prior to hitting the timing side bush. I suspect the spring was getting coil bound before the ball had cleared the oil gallery. The bike had seized on three occasions prior. Having removed the anti wet sump valve, we ran the bike with no ball and spring (AWS) for a while and the oil flow back to the tank was excellent. We then fitted an outboard Anti wet sump valve (I know, not everybody likes or approves of them) and this prevented wet sumping and did not affect the oil return to the tank. More recently, a different mate had poor oil return to the tank. This turned out be a damaged pump. The circlip had come off the end, bits of mazak had dropped into the timing case and the crankshaft worm wasn't engaging properly with the oil pump gear. We fitted a second hand pump - all good. If your bike has an SRM anti wet sump valve, that's the first thing I'd remove.

I had an engine SRM end fed many years ago and had the same problem of oil not returning properly. I also removed the ball and spring from the back of the oil pump and fitted an external AWSV. It has since done almost 100,000 miles with no recurrence of the problem.

[BagONails]

Just to recap. If I'm understanding the main thread here we are saying that the SRM ASV, an accessory which is fitted in the 'Feed' line before the oil pump is actually starving the oil pump of oil to the point that this showed up as a reduced oil return? Reduced because insufficient oil was being supplied in the first place with attendant low/intermittent oil flow and pressure to the engine bottom end!

Or could it be a sign that the oil pump is below par and not able to draw hard enough on the feed line to open the ball against the spring?

The original one behind the oil pump is on the pressure side of the pump and should never cause an obstruction to oil delivery into the main gallery.

Are these still being sold by SRM's? They deserve to hear all about this.

[Rex]

The issue there is that the pump doesn't "draw" on the feed line. It's gravity fed.

[Else]

Thanks for all the replies and helpful comments.

Just want to say that there is very good flow of oil back to the tank now cold and hot. It is an almost continuous flow rather than the intermittent spurts that I used to get with the ball and spring fitted. I'll worry about wet sumping if and when it happens.

Else

[Rex]

Shouldn't be continuous after the first minute or so of running after a start up.
Granny's eggs again, but the scavenge side pumps more than the delivery side.