Got my brand new spare M20 oil pump out today, and it is completely locked up
Seems to be a common problem with those Zamac/Mazac castings.
Is there anybody who can make it running again ?

email (option): viaconsu [at] planet [dot] nl

Yes! Hans Muller in NL can. He will take the whole thing apart and by putting fine lapping paste on each gear spindle in turn until they all turn freely. The ones that can't be turned are turned by their next door neighbour with the drive dog and a pair of pliers. Backwards and forwards till each little gear is free. Also some lapping paste might be needed between the gears and Mazac end plate.
Once it is all thoroughly cleaned up and oiled, you should be able to turn the pump by hand.....even if a bit stiff. Careful not to over tighten the mounting bolts though. Ron

email (option): ronpier@talk21.com

somewhere along the line i was told to emurse the pump in oil when out of the engine

It might be due to time travel on Saturday night, but I had thought I saw somewhere in a link from this site - that someone now makes a replacement stainless steel body for this type of BSA oil pump

I had thought it might have been a Dutch company ??

Jo'b

email (option): Jonnyob1@googlemail.com

I think Drags make a pump from high quality steel.

Ron

email (option): ronpier@talk21.com

Jan de Jong from ABSAF makes new oil pumps with more output they are verry expensive bug olso verry good bud for an M20 I was looking at my oil pumps and there was one with other sprocket from the five pumps was this was the only one can anny one explane this Gr. Theo Schipper

email (option): oldbikes@kpnmail.nl

As previously mentioned, this seems common, my question is do they nip up in normal running? If so do they need checking and how often?

Theo, I think they made pumps with 9 or 11 tooth gears, for different bikes?
Cheers Pat

Here's a link to the Draganfly info page about pumps
cheers
Pete
http://www.draganfly.co.uk/data/pdf/sump_pump.pdf

email (option): petercomley@web.de

Hi Pat...The process seems to happen over a period of years (or decades?)...I haven't had any further problems with pumps I have 'lapped in' to free them up. Like Hans I have had the problem with NOS pumps as being an 'unstable' material it degrades with age, not use..(and bear in mind they are still being used well beyond the time intended by BSA)..Gold Stars had the higher output pumps that you mention..As yet I have not bought a replacement after market pump body as I have always had good service from 'lapped in' original units..These days I have to do the job on most of the engines I rebuild and on the subject of recommissioning barn find bikes without rebuilding them (which I wouldn't do personally) an inspection of the oilpump should be near the top of the list of things to do.......Ian

email (option): ian@wright52.plus.com