CB72 oil pump - is it possible to test it before reassembly?

[hondamancbr]

I'm now about 18 months into a CB72 restoration over in the UK. This has involved a complete dismantle of all engine and cycle parts. Just about the only part I haven't dismantled is the oil pump. Now I'm about to rebuild the engine, my question is this: Is there any way I can have the oil pump tested to see whether it's working properly before I bolt it back into the crankcase? Unfortunately, I have no information from the previous owner (since deceased) as to whether the pump was functioning when the engine last ran over 20 years ago. I found some scuffing in the cylinder bores (since re-sleeved) when I took it apart, which suggested to me that there may have been a partial seizure back in 1983. The oil pump wheel runs smoothly, and I don't want to dismantle it unnecessarily. Any thoughts/suggestions will be most welcome. Many thanks. Art

[LOUD MOUSE]

I take the pump apart and inspect the gears and area where they fit for scars or obvious damage. If the parts are good I assemble it and put oil on all parts as I do. I then use my wire wheel on my bench grinder and spin the drive wheel. I then put my finger on the hole where the oil will be pumped into the engine. In one direction there will be pressure and when I turn the pump around there will be suction. If I find both I use the pump. .........lm

I'm now about 18 months into a CB72 restoration over in the UK. This has involved a complete dismantle of all engine and cycle parts. Just about the only part I haven't dismantled is the oil pump. Now I'm about to rebuild the engine, my question is this: Is there any way I can have the oil pump tested to see whether it's working properly before I bolt it back into the crankcase? Unfortunately, I have no information from the previous owner (since deceased) as to whether the pump was functioning when the engine last ran over 20 years ago. I found some scuffing in the cylinder bores (since re-sleeved) when I took it apart, which suggested to me that there may have been a partial seizure back in 1983. The oil pump wheel runs smoothly, and I don't want to dismantle it unnecessarily. Any thoughts/suggestions will be most welcome. Many thanks. Art

[hondamancbr]

Thanks very much for your advice - much appreciated. Here's hoping for good pressure! Art.

[Phil-UK]

Hi

I had my CB72 seize up a couple of years ago and not being sure about the pump managed to
get a new one. What I did was when the engine was assembled, I took off the L/H fron tappet cover
and leaving the plugs out spun it over on the starter using a car battery.

After about 20-30 seconds you should see gouts of oil being sprayed into the valve cam area.
It was definitely strong enough to be seen as distinct bursts and not just a gentle weep.

The books talk about measuring clearances on the pump when stripped but this gave me a good reference for what it should do when new.

I asked a friend who works in the car industry and he said the "proper" way to test it would be to connect the pump to an electric motor, immerse it in oil and take the output to a vertical pipe
open at the top and see how high a head of oil it will maintain.
I think my way is easier .

Hope the rebuild goes well, drop me an email if I can be of any help ( I'm near Brighton ).

Phil Lou

[hondamancbr]

Hi Phil
Thanks for your suggestion. I think I'll probably try spinning the pump up dry before I put it into the crankcase to see if that generates pressure and then, when all's assembled and ready to go, see whether the oil is spurting into the camshaft area as you suggest. Thanks also for your offer of advice. I'm about 450 miles north of you (in Scotland). I'll be starting the rebuild fairly soon, but I don't think I'll be in a position to "fire her up" until sometime next spring. Work gets in the way!

Cheers
Art