Topic: CB - 500/550/650/750 stock -OR- Alternate carb measurements

[Soos]

Ok, I have heard a few times over "will XX carbs fit on XX bike?"

I have measured stock cb650 carbs (CV and NON-CV) and CB750 carbs....
I know cb650 and cb750 caerbs are spaced so closely that interchanging is possible.


Does anyone have a set of calipers and CB550 carbs laying around they can measure?



I am mainly wondering about the spacing from carb to carb.(center to center)
Any other measurements welcome as well.
OD of the airbox side and engine side of the carbs, Venturi size, carb body length, etc..


I will drag up my measurements and post them here. Got some for cb750, 650, and kawa ninja as well.

ANY other bike carb measurements greatly appreciated as well...


l8r

[SteveD CB500F]

Sounds like a candidate for the FAQs.

You collect the info - I'll post it.

Steve

[bwaller]

1977 or 78 CB550 and PD series carbs

depth (front to back)               -100mm
OD (engine side)                     -32.9mm 
OD (airbox side)                      -38.1mm
spacing between #1&2 and 3&4 -75.8mm  (c to c)
spacing between 2&3               -81.1mm

Venturi, beyond my capabilities... supposed to be 22's,anything but round and tough to measure.



CB500 and 627B series

depth (front to back)             - 101mm
OD (engine side)                     - 33mm
OD (airbox side)                      - 38.8mm
spacing between 1&2 and 3&4   - 69.6mm  (c to c)
spacing bewteen 2&3               - 69.7mm

again these are supposed to be 22mm carbs

[Soos]

That would be awesome Steve!

PD50A stock '79cb650 carbs:
Type of carb                  - Mechanical linkage
depth (front to back)       -99.8mm
OD (motor side)              -35.4mm
OD (airbox side)              -45.8mm
#1&2 and 3&4 (c to c)     -76mm
between2&3  (c to c)      -80.9mm


"7A" '73(?) stock cb750 carbs:
Type of carb                  - Mechanical linkage
depth (front to back)       -88.26mm
OD (motor side)              -36.95mm
OD (airbox side)              -40.08mm
#1&2 and 3&4 (c to c)     -76.3mm
between2&3  (c to c)      -81.5mm


VB44a stock '81 cb650 carbs:
Type of carb                  - CV
depth (front to back)       -122.1mm
OD (motor side)              -39.8mm
OD (airbox side)              -53.8mm
#1&2 and 3&4 (c to c)     -66.3mm
between2&3  (c to c)      -92.7mm


'85 kawasaki ninja (zx600 - A1 motor AKA GPZ600) carbs:
Type of carb                  -  CV
depth (front to back)       -94.1mm
OD (motor side)              -38mm
OD (airbox side)              -50mm
#1&2 and 3&4 (c to c)     -67.5mm
between2&3  (c to c)      -91.4mm

Whew....
Looked through my posts, and still had to drag out each set to measure something on each set.


Keep 'em coming guys!


If you have a set that is already listed, but yours measure differently post it anyway.
Perhaps there are minor changes through the years/models that will show with information from enough people.



l8r

[billybobobrain]

hey this one kinda petered out to soon. Has anyone put 750 carbs on a 500? the spacing on my 72 750k2 carbs is 78mm 1,2,3, and 4, my buddy has my old 500 and I might be upgrading.

[bwaller]

I've seen several racing 500's with 750 carbs. It might help to use the 77-78 550 intake manifolds. I remember mounting some on a buddies stock 500 in the early 70's and never really got it well sorted.

[SteveD CB500F]

FAQ is here

More info required please!

[Soos]

The measurements I would like to see are for the '77/'78 cb750 pumper carbs.
Also the automatic 750's(750A)!!


thnx for linking the info into the FAQ Steve!


l8r

P.S> Anyone out there have any webbers out there they can measure?
Mikuni smoothbores would be another nice one.

[Soos]

hey steve,

Thought I would add the venturi size on those carbs as well if I haven't already.

cb650 PD50a carbs 26mm venturi
my '73 "7A" carbs 28mm venturi
have to re-check on the CV 650 carbs...
The CV kawasaki 600 ninja carbs('84) are 32mm


l8r

[manjisann]

I'm looking to put some 750 carbs on my 80 CB650C and found this info immensly helpful. I wish there was more of it for more of the 750 years and models. Either way, here are the specs on my carbs, hopefully they'll make it into the FAQ as well 

PD50B (after that it has an A inside a square then RJ) 1980 CB650C

OD Airbox Side: 35.46mm
OD Engine Side: 45.95mm
Front to Back: 100.13mm
Top to Bottom: 149.58mm (this doesn't include the overflow tubes or the cable control linkage)
Approx Center: 1-2 77.04mm
Approx Center: 2-3 81mm

I used calipers that are in inches and then converted them to metric. The measurments should be fairly accurate though.

Hope this helps,

Brandon

[SteveD CB500F]

I have updated the FAQ but need lots more measurements...   

[manjisann]

What other measurments from those carbs I have can I get for you, I'd be happy to do it? What is the venturi soos had listed?

Edit- oh, and they are Mechanical Linkage

Brandon

[SteveD CB500F]

The venturi is the diameter of the narrow throat inside the carb. The relationship between this and the inlet diameter is important as it is what dictates the acceleration of the air through the carb causing the vacuum that sucks the fuel out of the jets.

[Soos]

PD50B (after that it has an A inside a square then RJ) 1980 CB650C

PD50b carbs are basically PD50a carbs with slightly diff. internal bits I believe.


l8r

[trueblue]

I've been researching different carbs for my 79 650, I've found some Mikuni CV carbs off a GS650E Suzuki that are a close fit.
They measure
OD Airbox Side: 52mm
OD Engine Side: 40mm
Front to Back: 114mm
Top to Bottom: 150mm (this doesn't include the cable bracket)
Approx Center: 1-2 & 3-4 75mm
Approx Center: 2-3 81mm
Venturi size is meant to be 32mm but I have no way of verifying this.
To fit these I'll probably have to use the boots off of the late model SOHC 650 with CV carbs, the only problem with this conversion will be the lack of sync ports in the carbs, on the zook they are in the boots.  I was thinking of modifying the boots and putting sync ports into them.