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Morgo plunger pump for singles

Posted: Mon Jun 25, 2018 8:43 pm
by robjameson
Has anyone fitted a Morgo plunger pump to a single?

If so, is it worth the money for the improvement?

My pump seems to have a weak scavenge, and I have eliminated all other causes.

Re: Morgo plunger pump for singles

Posted: Mon Jun 25, 2018 8:59 pm
by dave.owen
No experience, but with a good original pump there shouldn't be any problems. They are more than up to the job.
Have you checked that you have no air leaks on the pickup pipe from the sump.

Re: Morgo plunger pump for singles

Posted: Mon Jun 25, 2018 9:13 pm
by robjameson
Yeah, I had the engine apart last year and actually removed and refitted the scavenge pipe, and made sure it was fully sealed before refitting.

Tested it too.

Might have to invest in a new oil pump and see if it makes any difference.

Re: Morgo plunger pump for singles

Posted: Mon Jun 25, 2018 10:15 pm
by Simon.Gardiner
Agree with Dave, standard pump is more than up to the job - what are the 'weak scavenge' symptoms Rob, sump full of oil and pump never returns a continuous stream of oil?
My quick test for a half-decent pump - take it off, swill it with petrol or paraffin to get rid of the thick oil, then with thin oil see if you can get the ball valve to 'click' with compressing the air when you push a plunger down.
If it doesn't (or as an additional check) push the plunger down, put your fingers over the feed/return holes and see how much vacuum is created when the plunger is pulled out and released - I'd hope the plunger would at least return half-way back when released quickly.
In my experience a good pump will 'click' the ball valve and return the big return-side plunger with just paraffin in it.
Probably teaching folks to suck eggs with this, but you never know.....


Re: Morgo plunger pump for singles

Posted: Mon Jun 25, 2018 10:24 pm
by robjameson
The symptoms are what I would class as excessive breathing from the crankcase vent. In my experience this is usually down to either blow by or weak scavenge. The former it isn’t, it had New piston and rings not long ago and gap is good.

I don’t get a good steady stream back up to the oil tank at idle, which increases as you up the revs, but certainly not as strong as I’ve had previously, and with other bikes.

I’m just trying to eliminate. I know I ended up getting some parts mixed up a few years ago, where I think my best pump went on a VH I subsequently sold. I have a feeling that the pump on the bike I previously removed due to some misdemeanour or other.

I suspect swapping the pump will confirm if I’m peeing in the wind or not.

Re: Morgo plunger pump for singles

Posted: Mon Jun 25, 2018 11:02 pm
by jj.palmer
Rob, before you risk your money you are quite welcome to borrow the pump off my 1955 NH350, it may confirm your thinging, this NH350 pump is scavenging ok.

The bike is not currently being used so there is no problem, as you know I am approx 8 mile away.

John P.

Re: Morgo plunger pump for singles

Posted: Mon Jun 25, 2018 11:28 pm
by steve.clarke
I fitted a Morgo to my 58 VH not that there was any thing wrong with the old pump but as they are the heart of the engine and available at a reasonable price it was my preferance, the most noticeable difference is at tick over you get a stream of oil not the bubbles, and when revved there is a marked increase in the flow rate, is it that much better than the original pump? hard to say unless you have a new old stock pump to test them back to back but i'm pleased with the operation of the Morgo, i did have a video of the return flow but i can't find it on this Lap top if I do I will post it up.

Re: Morgo plunger pump for singles

Posted: Tue Jun 26, 2018 12:21 am
by nevhunter
There appear to be two distinct types of spring used in the ball valves. The square headed plugs that hold them in are different in detail for the different springs. The long straight springs don't work well sometimes. They end up too strong and distort. The others are smaller, lighter wire and conical and don't fit the "other" plugs properly. Other times I've had grunge under the ball and it doesn't return reliably. The balls are a "funny" size and I've seen the wrong sized ones used. There's the "usual" air leaks problem as a Cracked copper pipe and the "extra" thin washer gasket under the pump not fitted.
Using an oversize pump gives problems . Just about all those who raced tried them (Converted Triumph pumps etc). Most found the motor ran hotter and oil poured out everywhere and power was down due to poor scavenge of the larger volume of oil delivered. the Ariel sump is just not well designed in the way the scavenge is arranged. Oil doesn't necessarily obey gravity absolutely when engines are doing lot 's of revs and you need a scraper to direct it into the pick up point. I would recommend that you don't go bigger than the 49A stamped pump for normal work unless you install a scraper and that's not particularly easy or a prefect cure. the ball seats are quite a half spherical shape so striking the ball with a hammer won't change much if the seat is worn out of shape or the ball worn or the wrong size, or the spring not correct for the "model". Being IN TOUCH with other ARIELS I am aware of others having oil pump troubles in the scavenge department fairly often these days The return should have bubbles or intermittent return as the scavenge is many times more than the delivery rate and at different revs the oil goes to different places and more will drain down at idle when gravity is more of the picture. When people develop race engines it's surprising, (as they discover) where large quantities of oil congregates.. The pistons are mighty effective air pumps and the sump capacity is not large. '"Anyhow" the originals work OK for the average conditions Nev.

Re: Morgo plunger pump for singles

Posted: Tue Jun 26, 2018 10:26 am
by robert.clark
I fitted one - no issues

Re: Morgo plunger pump for singles

Posted: Tue Jun 26, 2018 10:53 am
by Keith.owen
I fitted a Morgo because I needed a pump (I thought mine was good, but) and wanted to eliminate as many variables as possible. I can't say that it cured my wet sumping problem, since, I also changed the timing cover (in case the original was warped) and fitted an extra paper washer; I cued the problem.

The pump seems to run well although my normal running pressure is IOR 22psi (assuming the gauge is accurate).

I fitted a Yamaha reed valve to the machine (crank case timing side) which meant that leakage of oil was minimal. However, having rebuilt the engine (the old bore was shot) leaking and ejection of oil from the breather has improved further. I o think that a worn bore can cause all sorts of unwanted side effects.

So, the verdict on the pump is that its ok, but if you have a good Ariel pump it will be more than adequate for the job. If your bore is good, check that there's not an air leak in the oil return circuit before changing pumps, etc.