Author Topic: Billet CNC Oil Pump Rotors (Now in stock!) - CB500/CB550 anyone?  (Read 12971 times)

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Offline Medyo Bastos

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #25 on: August 23, 2018, 03:57:34 pm »
Got mine, ‘preciate it


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Online PeWe

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #26 on: August 23, 2018, 10:04:52 pm »
I have a strong feeling that I soon will restore an old pump. Gasket kit needed too.
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Online PeWe

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #27 on: August 30, 2018, 09:38:06 am »
Rotors arrived today! Thanks!

Waiting for Vital seal kit. An old pump will be restored this winter.
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline kmb69

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #28 on: September 05, 2018, 08:02:58 am »
Received mine. Thx
Looking real good Mirko!


Offline jus4selling

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #30 on: September 17, 2018, 10:51:31 pm »
These look slick!

Online PeWe

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #31 on: March 13, 2019, 12:48:11 pm »
I finally installed the rotors in a pump that has got the Vital seal kit.
The rotors have a fantastic tight fit without any metal contact when rotating the sprocket as old Honda due to scuff marks that also sat looser in the pump body.

I have one more pump that will get a set of these nice rotors. Both my bikes will get a pump swap, upgrade of pressure when oil is hot.
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Online PeWe

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #32 on: March 25, 2019, 09:20:15 am »
Another set arrived today
Thanks Mirko for improving the CB750 !! ;)
Here the new set beside my first installed in a pump that will enter my K6 at next oil change. I'll test the pump sitting in now.
Both pumps have the Vital motor parts seal kit installed.
// Per
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline MessnerMoto

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #33 on: March 25, 2019, 02:38:53 pm »
Keep them oiled Per ;)

that 4732  hard steel is very prone to surface rusting when exposed to elements. Not important from functional point but I like them to shine ;)
« Last Edit: March 25, 2019, 03:10:14 pm by MessnerMoto »

Online PeWe

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #34 on: March 26, 2019, 04:38:04 am »
I have them stored in the oily bag they came in. My garage is otherwise dry and the warmest room of the house.
« Last Edit: March 26, 2019, 12:52:15 pm by PeWe »
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Online PeWe

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #35 on: May 14, 2019, 09:59:43 am »
Update:
My blue modified K6 got new rotors. Road test, warm oil and low idle worked fine.
No flickering oil warning as before at 1000-1200 rpm when oil temp is 100-120*C.

Last ignition setting took looong time cooking the oil at idle.... Easier with 4 arms..

These rotors a cheap ensurance for a good engine.
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline turboguzzi

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #36 on: May 14, 2019, 01:07:01 pm »
hei mirko

seen that you didnt say if the 500 dimensions are the same as 750...
Appears the CB500/550 rotors are  40.54mm OD, 27mm Wide, 11mm shaft, and 3.4mm offset.
how does it sound?
dont know how kmb measured, but if difference is in the 0.1mm range, id say its the same section rotor

Offline kmb69

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #37 on: May 14, 2019, 03:59:59 pm »
hei mirko

seen that you didnt say if the 500 dimensions are the same as 750...
Appears the CB500/550 rotors are  40.54mm OD, 27mm Wide, 11mm shaft, and 3.4mm offset.
how does it sound?
dont know how kmb measured, but if difference is in the 0.1mm range, id say its the same section rotor

The 750 rotors are 18mm and 12mm wide.

Offline turboguzzi

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #38 on: May 15, 2019, 11:32:11 am »
tnxs kmb
would be less concerned about width, as you can slice the section at different points.

if the section of the pump rotors is the same, then he doesnt need to develop new cad

Offline kmb69

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #39 on: May 15, 2019, 08:52:58 pm »
tnxs kmb
would be less concerned about width, as you can slice the section at different points.

if the section of the pump rotors is the same, then he doesnt need to develop new cad

Pretty sure the rotor profiles are the same other than the width.
Mirko could easily make the 500/550 rotors if so inclined.

Offline turboguzzi

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #40 on: May 15, 2019, 11:46:05 pm »
find it interesting that the width of the supply side of the 750 is so much smaller than the 500...
honda learned a lesson from the 750 and applied it to the 500? or do the 750 rotors spin much faster?

Offline flatlander

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #41 on: May 16, 2019, 09:11:50 am »
i don't know the answer to that.
but posting here to see if or when he makes these rotors for the 550.

Offline MessnerMoto

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #42 on: May 17, 2019, 01:08:43 am »
Yoss I am back to Milano on 20th. We can test try 18mm rotors in your oil pump casing just to see if profiles are the same.

Offline kmb69

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #43 on: May 17, 2019, 10:11:13 am »
find it interesting that the width of the supply side of the 750 is so much smaller than the 500...
honda learned a lesson from the 750 and applied it to the 500? or do the 750 rotors spin much faster?

The 750 is a dry sump system with a pressure rotor and a sump rotor.
The 500/550/650 is a wet sump system with a single rotor set pulling and pushing.
The 750 rotors are 30mm combined.

Offline turboguzzi

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #44 on: May 18, 2019, 02:26:34 am »
hei kmb, i am of course aware of that, still, if you look only at the "pressure side" feeding bearings, etc, it's notable how much wider the 500 rotor is. IMHO, the fact that the pressure side in the 750 is fed from the oil tank and in the 500 it sucks from the sump, would make very little difference to the volume per pump revolution. Just a side conversation/food for thought.

Offline Rod

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #45 on: May 18, 2019, 09:12:15 am »
hei kmb, i am of course aware of that, still, if you look only at the "pressure side" feeding bearings, etc, it's notable how much wider the 500 rotor is. IMHO, the fact that the pressure side in the 750 is fed from the oil tank and in the 500 it sucks from the sump, would make very little difference to the volume per pump revolution. Just a side conversation/food for thought.

+1 TG - increased pressure on the feed side will have absolutely 0 effect on the mass pumped as we are looking at fluids not gases (the density of fluids can be increased very marginally e.g. deep ocean depths, but extremely high pressures are required).
« Last Edit: May 18, 2019, 11:10:28 am by Rod »

Offline turboguzzi

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #46 on: June 04, 2019, 02:44:24 pm »
Mirko visited me today and after a quick check it's official: 500/550 rotors have the same section as the 750's. BTW, width of the 500 rotor is 22mm not 27....
Pretty sure he will reveal more details soon.

Offline MessnerMoto

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #47 on: June 05, 2019, 06:02:02 am »
Yes like Yoss said we tested my CNCed(18mm of thickness) rotors and they fit perfectly. Picture provided ;)

It is good that we tested because we discovered that rotors in cb550 are 22mm thick :)


Offline MessnerMoto

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Re: Billet CNC Oil Pump Rotors (Now in stock!)
« Reply #48 on: June 09, 2019, 02:59:17 am »
Is there people interested in CB500/550 CNC rotors?

and is cb650 oil pump the same?
« Last Edit: June 09, 2019, 03:09:59 am by MessnerMoto »

Offline turboguzzi

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Re: Billet CNC Oil Pump Rotors (Now in stock!) - CB500/CB550 anyone?
« Reply #49 on: June 09, 2019, 02:57:38 pm »
650 rotor should be wider, not sure by how much... brent?