Singles oil pumps

[nevhunter]

Paul is completely correct. These are the simplest of pumps and any vacuum is partial in this instance. IF the ball doesn't seat (and unseat freely) it can fail. They also don't work well at high rpms. A roller big end is not too fussy about a bit of froth but PLAIN bearings are Nev

[Geoffrey Lord]

I have read this topic with interest as having just got my 1930 Model A on the road with a Morgo pump installed I have the smoking problems talked about. As I don't have the oil scraper ring it all makes sense.

Months ago, when I was rebuilding the engine, I determined that the feed plunger was worn so I spent a few happy hours making a new plunger about 1thou oversize. On the bench this seemed a good fix but then I discovered the Morgo pump and went with that not realising the smoking implications.

So, having done a few smokey miles with the Morgo I decided to refit my overhauled original pump. This seems to be working ok in the garage. I'm getting about 10psi on a fast tickover and oil returning to the tank, so pretty happy with that. BUT I'm a little nervous of taking it on a run with such a tiddly plunger as compared with the Morgo!

So here are a few things I have been thinking about that I would like opinions on.
Firstly should I not be too worried by the small plunger if I'm getting returning oil and the normal small pressure on the guage?
Has anyone any thoughts about the Hawker pump? Is it similarly oversized as the Morgo?
Has anyone tried 'jetting' the feed to a Morgo to reduce the flow rate? Maybe this would enable one to maximise the flow before smoking becomes an issue.
Has anyone tried sleeving a Morgo and reducing the plunger size?
Cheers

[nevhunter]

For a normal bike the original set up is perfectly OK.ie Small plunger and no oil ring. Oil rings have a lot of friction. Till 1938 they didn't have oil supply to the rockers. After that it was still used till 1947-49 when an oil ring became standard with a larger pump plunger. The Morgo has an even bigger plunger.. The oil pressure is not an indication of engine condition or flow rate. It puts a back pressure on the supply and that registers on the gauge. It's an extra load on the pump also. Nev

[JohnnyBeckett]

hi i never had a problem with a Morgo plunger pump i would look at why the oil is not getting back to the tank if you are getting too much oil to the rockers fit a restrictor in the pipe to the rockers

[dave.owen]

A morgo or late larger plunger pump is not required on early singles with only compression rings.they pump too much oil over that required as Nev has said.

Dave

[paul.jameson]

My 1937 RH500 is still using its original small bore plunger and working perfectly well. But I have only just under 40 years and 40,000 miles worth of riding with it so far and no more than 468 miles in a single day so far.

[Roger Gwynn]

My single has always used a reconditioned original plunger pump, apart from a brief dalliance with a Triumph pump, 48,000 miles in 20 years. Currently using a Hawker pump as a long term test.

[Geoffrey Lord]

Well that's pretty unanimous then! Small bore pump it is. I actually summoned the courage to go for a short (7 mile) trundle to test my old pump with my mate following as mobile smoke dectector and the results were very encouraging. The report from behind was an improving picture the further we went, I guess residual oil in the exhaust was burning off at the start. The oil pressure was at about 6 psi when I got home although I guess that may drop a bit on longer runs when the oil in the tank is at full temperature.

Thanks everyone for the advice.