Why do they make new oil pumps for most BSA's but not for the B and M series? ABSAF who make the new Gold Star engines will supply a new oil pump that will fit the M20,M21 and B series bikes but is over $400 to the USA. If you have a BSA twin, BSA unit single, Triumph twin, Norton twin, Ariel square four and a number of other bikes you can get a new pump at reasonable price. Why not us? I have just spent hours lapping in a M21 pump body made out of the original mystery metal and have heard of cast iron and aluminum replacement bodies but can not locate any of them??????

Bruce

as far as I know you can buy most of the individual parts for the M20 oil pump from Draganandfly to overhaul the pump...

https://www.draganfly.co.uk/index.php/a65anda50/category/893-oil-pump

A reconditioned pump can be bought from Draganfly for 168 GBP (excl. shipping costs...)

email (option): mr.bighealey@hotmail.com

New Aluminium Oil pump bodies are available from de Groot in Holland.

Henk

New oil pump

email (option): ahum@quicknet.nl

Draganfly used to advertise new steel oil pumps.
But I haven't heard anyone on this forum about them.
Maybe no one ever tried ?

As the pumps never seem to actually fail I think most people will refit the old one...If they are aware of the lapping in procedure they will do that...

On that basis I imagine the demand for new pumps isn't that great...

Arguably, if the old pump works well enough fitting a new one will only achieve moderate gains in oil flow...

In my experience I have found most users of M and B Series singles will frequently not go for upgrade parts if they can get the original to work, even if not at 100%...For example, it's hard work selling new girder fork springs but I'm fairly confident that most M20s have never had a replacement and the springs are well out of the original tolerances..

However, they still go up and down.. ....

Gold Star owners on the other hand perceive the bike/cost benefit differently due to its higher value and consequently are happier to spend the money...

All my own bikes have had NOS original pumps fitted at rebuild during my ownership but people wishing to do that or fit a remanufactured pump are definitely in the minority..I got the last one from Hussein but I don't know if he has anymore available...Ian

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

The twins and some singles have plain bearings which are very sensitive to oil pressure.

B & M series motors are all balls & rollers with the exception of the little end and could probably run quite happily on splash alone as does a lot of stationary engines.

I have known single owners to pull out oil pumps that had bee in the engine for years only to find the shaft broken and the ends polished from running on one another.
Now while there was a lot of damage to the engine, they were running quite fine.

email (option): bsansw1@tpg.com.au

Hello Bruce,

Draganfly still has the rebuilt pumps as an exchange service:

First, they would need to have your old pump,
And then they would send a "New" one, using your old gears.

65-2589F Oil pump, large gear, EXCHANGE reconditioned (12T)
65-2619F Oil pump, small gear, EXCHANGE reconditioned (13T)

Best wishes,
Noam.

Why is my b31 wet sumping is it the pump

email (option): Zackdingle2000@yahoo.co.uk

Stuart Bray had some new oil pumps very recently at £250 each, still in the cosmoline...I paid £440 for the high capacity ABSAF oil pump for my Goldie project last year....
I also bought a NOS pump last year from America for £200(ebay)....

When I last rebuilt my B33 I had awful trouble with wet sumping..In the past I have always managed to solve this problem but even after doing all the usual things it still wasn't completely right...In the end I fitted a new pump and that cured it immediately...

I have some more information on oil pumps now and when time permits I've got to get a few out and do some accurate measurements to determine how the 'lapped' pumps compare to 1) a new one and 2) the information I have...

I think the most likely solution in the short term, after checking the anti drain valves are good, is to fit a new body if one can be obtained...As far as I'm aware Draganfly are not using new gears for their refurbished pumps and if that is the case the pumps aren't truly refurbished...I stand to be corrected on that statement but it's something to be checked if using the service...Ian

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

150 Euros plus postage for the de Groot oil pump body in aluminium...Ian

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