Topic: cb750 oil pump Discovery!!!

[Elan]

ok so this is a discovery in progress, that with your help could benefit us all 

So as you probably know, Ive had oil pumps on my mind- I've been having bits and pieces remade and I have been putting together rebuild kits. Well late one night I decided to buy some more oil pumps off ebay. Random stuff. One being from a Kawa kz750. The idea was to possibly provide kits to other bikes.
Looking at the kz750 pump, i immediately notice something. It has the same casting mark as the cb750. An eagle wings logo with a "1". So Honda was not making their oil pumps, they were being made by another manufacturer, who also made the pumps for kawasaki! Anyone know who this manufacturer was? The oil screen is the same exact oil screen as the cb750! But buy mine, its  much cheaper   

Anyway, I opened up the pump and it has one rotor. The rotor sits on a shaft that is 10.97mm, just like the cb750. The outer diameter of the rotor is 40.56mm, just like the cb750. the pattern is the same aside from a slight relief at the points(to reduce wear?). Same dowel key notch. the depth of the rotor is 16mm however. The cb750 has 12mm depth on the pump side and 18mm on the scavenge side.  so for this rotor (part #16154-003) you could just shave off 4mm and have a brand new rotor for the cb750. Did I mention kawasaki sells their rotors seperate (unlike honda) and they are still available?!?!  This rotor is $50 bucks.

So then I start snooping around the parts diagrams. who can sleep at this point anyway? all their rotors start with part number 16154.

16154-1056  - exact outer diameter, exact shaft diameter, same pattern, 18mm depth(same as cb750 scavenge) but pin key is different. the inner rotor has two notches (6;00 and 12;00) and they dont cut all the way through the rotor . Looks like you can just use the kawasaki dowel key and it would fit with no modifications. Two things to confirm: the dowel key diameter of the cb750 to see that the shafts' dowel holes are the same.  And, the depth at which the cb750 dowel key sits into the rotor- if it sits too deep, this rotor dowel notch would have to be cut deeper.  $50 bucks

16154-0037 - exact outer diameter, exact shaft diameter, same pattern, cant confirm depth but says d-14 in the title so I think 14mm. Would need to shave off 2mm to work as the cb750 pump side. this also would need the kawasaki key dowel scenario as explained above.   $44 bucks

16154-1115 - exact outer, exact shaft diameter, same pattern, 22mm depth.  double dowel key as mentioned above.

Theres about 70 more part numbers. i looked through a bunch and it seems they are either not deep enough, or might have a different sized shaft, but I didnt even get through half of them. and theres very little info.  The above parts are a lead, but there could be one in the bunch that is an exact fit.

Does anyone have any KAwa pumps laying around?

Now I wonder who is making suzuki pumps...

Ill try to get some pics up soon.

[stewonepot]

Keep on it elan!
regards Stew

[70CB750]

This should go to FAQ, before it gets lost.

[Don R]

!

[Garage_guy_chris]

Kawa-onda oil pump rebuild kits. sounds good to me! the other way i could see this going is to get the mystery company to reproduce replacement parts for us. I think the oil pumps are one of the few "holes" in replacement /  aftermarket parts for these old bikes.

Good work Elan!

[Jerry Rxman Griffin aka MuthaF'er]

And to think I thought that I'd stumbled onto something when I found out the Gold Wing oil pump used a CB750 seal that was not listed separately for a CB750.

Excellent sleuthing Elan. Looks like we need a discounted or even wholesale price on Kaw parts like Motogrid or ServiceHonda 

No word on my parts yet.

[754]

On a surface grinder you can grind about 40 rotors at a time..

[Retro Rocket]

Subscribed...

[Kingmambo]

Good work!  I can see the new television series coming - CSI SOHC!

[Elan]

This is the company:

[Ilja]

Nice discovery as my rotors look chewed up and I got kz750 pumps shelved... 

[SoyBoySigh]

BUMP!

That's some good info right there. Not exactly the same mystery I'M exploring, but still pretty damn good.

I'm interested in improving the DOHC oil pump, for my "CB900K0 Bol Bomber"  (an '82 CB900F based "homage" to the '65 CB450K0 Black Bomber) and I can't help but notice that the oil pump from the SOHC CB750A Hondamatic looks just about exactly the same!

I'm mainly interested in adding some wider rotors perhaps the engine side rotor run on the cooler loop and a proportionally bigger rotor running the engine's lubrication needs, and construction a wider housing via a sandwich of multiple housings sliced thin & stacked to add the extra width, and the CB900C/CB1000C type oil-pump COVER also sandwiched and stacked for the extra 1/2" or so of extra clearance.

And also possibly replicating a larger pump but with the one huge rotor across the whole width, for a system plumbing all oil through the filter, with either full volume through the cooler or a bypass run off the cooler & returning to the head via the tachometer drive hole with a spray-bar or drip-tray etc.

AND/OR something like the DOHC RSC factory works' twin-stage DRY-SUMP pump, with it's external "horse-head" fittings and external oil tank etc.

I'd just really like to explore any & all off-the-shelf possibilities for improving the DOHC lubrication system & oil cooler loop etc. If instead, there's the spin-off benefit of figuring out that the DOHC parts are better for the SOHC CB750A Hondamatic, so be it - so long as it helps to keep a few more older bikes on the road!

-Sigh.