Improved 350 Oil Pump

Both plugs out, electric starter for 10-15 seconds I get oil at the port.
 
Jays, by “inspection port” I assume you mean the top left rear cam box bolt that I call the witness hole?
that is the first place I check. After the first startup and warm up and shutdown I also checked the centrifugal oil purifier through the right hand clutch cover small round access panel to see if these was oil residue in there since it was dry and clean when I assembled the engine.
I don’t think there is any other than those two places to easily see oiling evidence.
Do you have a problem with your test engine?
 
Yeah. I don’t know if it’s moving oil but can’t prove either yay or nay.
Tomorrow, I’ll pull the filter cover and crank the engine. It should jet oil pretty hard. I can make other decisions then.

Thanks for your experience!
 
Given that this is a test bed, have you considered adding additional check ports in order to get a more complete understanding of the upward oil paths?
 
Only alternative I've seen mentioned is to loosen head nut on outer stud and check for oil.
Guess you could invent some sort of banjo fitting to screw onto stud but a lot of work for not much gain.
I seem to remember you need at least 350rpm but no idea where I read it in last ~50 years.
You have to fill the oil passages before you build any pressure, drill may not be up to the task?
I have a cheap high torque Harbor Freight ~400rpm drill I bought years ago to use honing cylinders, no idea if they still list it though?
Making an extension bolt to screw into crank end would probably be relatively simple?
 
Oh, you could drill and tap clutch cover 'underneath' after oil pump where it crosses into cover then drilling directs oil to transfer piece and centrifugal filter.
It's ~25 years since I did a 350, can't remember if you can just drill and tap for banjo or straight oil line fitting although I think it was more involved with new 3 screw cover or boss welded on?
I've done CB360's more recently but still 13~15 years ago, they were real easy and don't need any welding just pull plug on drilling then tap for banjo bolt/oil line direct to end of cam before filter.
After working on various different engines I guessed size of restrictor to stop too much oil going direct to cam (I 'gun drill' cam and add outlets bottom of each lobe plus bearing surface)
350 is lot more involved unless you remove tach or fit electronic one.
I found the fixture I used to make oil line/filter cover take for XS 650, it's 'sealed' so easier to make than CB350 cover/transfer piece.
I think I gave away the one for 350 (I've given away various fixtures over the years, it's often easier to make a new one if I need to than try and find space to store stuff)
Last one was a special piston holder for modifying CB750 pistons to fit 500F, I've never used Cycle World 'Gentleman's Express' measurements, for race motor no one knew if valve pockets would need modifying so I sent fixture for milling or turning tops (I hate the idea of clamping lightweight or any other piston in a vice)
 
Thanks, I like your ideas.
Here’s a brief overview of where I am.

I disassembled the gear pump for a deep dive into clearances. The parts were produced to my dimensions and of good quality throughout. No issues there.
Next, revisited basic assumptions of flow or displacement and approached differently from a gear space/cavity volume perspective-just wanted to be sure. Results better than originally calculated.
Remounted the piston pump with oil now flowing out of the inspection port.

An observation is the suction screen may have been clogged. This engine was pretty nasty and I rigorously cleaned but… anyway, a clogged suction could cause a fail like this. It didn’t look that bad but I’m learning on this application too, so there is that.

Next step while the OEM pump is mounted is to get the data. Ensured sump screen is clean.
Short of adding an inspection port on the crankcase, the top left rear port is still the best.

Modifying the transfer piece is still an item, just not yet. I’m not a progressive, but in development testing, progression is progress.
 
Todays results.
The gear pump does indeed move 2x more oil, math does not lie in positive displacement pumps.

Pressure marginally reflects this.
The transfer piece mod on this engine does improve, marginally as well.

I was able to find a gauge scale that will measure inches of water column or “WC.

Oiling orifices are so large in this engine as to make pressure a questionable comparison.

Visual inspection of a running engine through the tappet covers show much more oil is to the top but is subjective in nature. Still, I made a heck of a mess!

Calling it a success.
 
Sounds good, Jay! Did you notice any further issues with the suction screen?

Jays100 said:
The gear pump does indeed move 2x more oil, math does not lie in positive displacement pumps.
Click to expand...
Were you measuring volume flow? I realize you may wish to hold back any trade secrets and I respect that concern – I'm just curious.
 
Jays100 said:
Visual inspection of a running engine through the tappet covers show much more oil is to the top but is subjective in nature. Still, I made a heck of a mess!

Calling it a success.
Click to expand...
I would call that success as well, normally you only get a bit of oil spotting from rocker arms and some oil running out of exhaust side where rotating cam throws it..
'heck of a mess' may not be scientific but it's much better description for us :cool:
 
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