HELP NEEDED KZ400

Have a customer with a KZ400S. He disassembled his carburetor assembly totally and sent the parts in a box. Box was BADLY damaged in transit (THANKS USPS!) The box had obviously been open and re-taped very crudely. When I got the box, only one carb body, a small plastic bag of small internal parts and the carb bracket was in the box AND an auto clutch plate. The customer and I aren't shocked by the lack of carb parts (tops, bowls, slides, springs, and one carb body missing) but a CLUTCH PLATE?

Anyway he has a 1976 KZ400S. I have the Kaw Factory Manual section for the carbs for that model. He is supposed to have a CVB36 Keihin assembly. I measured the ID on the remaining carb body that was in the box. It measures 32mm - It is the type with the all aluminum slide/diaphragm. It looks like the one pictured in the Kaw manual for that year. What is up? I thought the 32mm KZ400 carb had a rubber diaphragm and looked similar to the KZ440 carb (from memory).

Can anyone tell me how to ident a 76 carb? I am confused. Any help would be much appreciated. Fellow is a member of Odd Ivar's 400 bunch.

You might ask member Ibsen22000. I believe he knows the 400 just about as much as one could.

I know... Odd Ivar = Ibsen22000... was hoping to get a quick answer from a 400 owner.

I just rebuilt 76 KZ400 S2 (Special) carbs a few months ago. Stock has the metal-piston slides. The 76 D3 (Standard) model also had piston-slides. I believe that 77 was a transition year and that's when you'll see the rubber diaphragms. I had a 77 with slide pistons, but it may have been a 76 model sold in 77.

Strangely, most kits are for 74-75 then 77 and later. They seem to skip the 76 even though it's very similar to the 74-75. I know z1 carries the pre-formed bowl gaskets, though.

One thing, make sure the main jet is installed correctly. If the oring is off of it, it's difficult to tell which way the jets go in. I made this drawing for the 76 400 S2

Also make sure that main-jet plug does not leak or it will run super rich.

The idle circuit has two jets stacked on top of each other. Both are 35. One is a simple jet, and the other is a jet with emulsifier tube attached. The emulsifier jet is deeper in the hole, and the simple jet screws in on top of it.

Another thing, the layout of the air jets can be questionable since they will physically interchange, but have different size orifices. The main air jet (#40) has the smaller orifice. The main air jet goes between the pilot air jet and the screw that holds the plate. In other words, it goes in the middle hole of the three threaded holes. The pilot air jets (#90) and the screw that holds the small semi-circle plate go in the other two threaded holes. (Those will be self-evident.)




Post edited by: loudhvx, at: 2007/07/26 14:49

I have rebuilt most years but need application help. The guy said he had a 76 KZ400S. ONE of his carb bodies was left in the damaged box. It appears to be 32mm. The 32mm was measured on the cylinder head side venturi on the inside diameter. I have been told the carbs are CVB36 and to me, that implies a 36mm engine side venturi ID. Are the 76 carbs 36mm ID or 32mm?

Actually, I designed new intake manifold/carb holders for that bike. In doing so, I had to accurately measure the stock intake manifolds (so I made a drawing).

The throats were 32mm on the carbs, but here are the intake manifold dimensions I drew several months ago:


I know for a fact that the carb's bore matched the manifold's bore (32mm) because that is one dimension I had to stick to in making the new manifolds.

Post edited by: loudhvx, at: 2007/07/26 18:29

The CVB36 designation had me snookered for sure. Thanks!

Actually I just read the carbs are CV32 in the factory service manual.

EDIT: according to Ivar the 74 to 76 carbs are CVB36 (even though they measure 32mm)and the typo is the "CV32" on page 5.

77 and later used the CV32 carbs.

Post edited by: loudhvx, at: 2007/07/27 15:37

I dunno.. the 76 manual says they are CVB36. The owner has a 76 S model. I have one of his carb bodies. It is a 32mm venturi just like the one you pictured. He told me that the carbs should be CVB36 but they are 32mm... I think there is a mistake floating around in the manual perhaps. The all metal slide carbs don't come in 36mm I think. At some point, I guess I will have to sit down and look at all the info available and try and sort out the 400 carbs... I like the metal slide Keihins... solid carbs with few faults... only issue I know is the shaft penetration of the venturi causes vacuum leaks if the seal at the outside of the shaft isn't good.

I have the blue Kawasaki KZ 400 manual 99997-710-05 which is the 1976 4th revision with a 1977 carb supplement. It has the specs on page 5 and it says the carbs are Keihin CV32. EDIT: but that is a misprint. It should be CVB36.
On the back cover it says the 1977 KZ400 (D4 and S3) use different carbs, but the carb supplement also calls the newer carbs the CV32. EDIT: the newer carbs are indeed CV32.

However, I have a PDF copy from Ivar, and it's the 1978 5th revision and his manual calls it a VB32. EDIT: this is also a misprint. It should be CVB36.

I'm not sure if the diaphragm-slide (77 and later) carbs swap with the piston-slide (74-76) carbs, or not.

Post edited by: loudhvx, at: 2007/07/27 15:41

EDIT:According to Ivar, these listings for cv32 and vb32 are misprints. They should say CVB36. The 77 and later are CV32.



Post edited by: loudhvx, at: 2007/07/27 15:43

I think the 74/75 assemblies had identical carb bodies and brackets but the slides were dished, rather than flat on the bottom (slide cut out). There were various air/jet, jet needle and main jet combos used from 74-76.
I had the metal slide carbs marked CVB36x2 but I think that is definitely a typo. The 76 carbs have flat bottoms on the slides but are otherwise similar to the 74/75 except for jetting. The 77 carbs are the rubber diaphragm CV32x2 type. I am still filling in info when I get a the opportunity. If any of the 400 owners want to jump in and point out errors or additions, this would be helpful. If I get this stuff correct, I guess I will post it somewhere, like in the filebase or article section?

1974 KZ400 1975 KZ400D 1975 KZ400S

Carb Keihin CVB32 x2
Three assemblies KZ400 to #001436 KZ400D 001437-013414 KZ400S 013415-029327
Main jet 130
Main air jet 40
Slow air jet (see jet needle spec)
Slow jet (see jet needle spec)
Pilot jet 35 (pilot jet is small barrel shaped jet sitting over slow jet)
Pilot screw 1 5/8 +/- 1/4 turn
Fuel level 2 ~ 4 mm
Starter jet 72 (looks like main jet- next to press in main jet)
ID Mark 757-A
Jet needle / Air jet combo:
jet needle 303008 slow air jet 100 slow jet 40 main jet 135
jet needle 303009 slow air jet 90 slow jet 35 main jet 125
jet needle 303011 slow air jet 90 slow jet 35 main jet 125
Comment - Round metal vacuum slide w/dished bottom

1976 KZ400D3 KZ400S2

Carb Keihin CVB32 x2
Main jet 130
Main air jet 40
Slow air jet 110
Slow jet (see jet needle spec)
Pilot screw 1 5/8 +/- 1/4 turn
Fuel level 2 ~ 4 mm
Starter jet 68 (looks like main jet- next to press in main jet)
ID Mark 757-A
Jet needle 303011
Comment - Round metal vacuum slide w/flat bottom

1977 KZ400D4 KZ400S3

D4 Carb Keihin CV32 x2
Main jet 95
Main air jet 50
Slow air jet 130
Pilot jet 35
Pilot Screw 1 1/2 +/- 1/2
Service fuel level 2 ~ 4mm
ID mark V52-A
Comment - rubber diaphragm on slide

1978 KZ400B
Carb Keihin VB32

1978/79 KZ400C1/C2
Carb Keihin CV32 x2
Main jet 90
Main air jet 60
Slow air jet 115
Pilot jet 35
Pilot screw 1.0 +/- 3/8
Service fuel level 2.5mm
ID Mark V54A

1979 KZ400 LTD
Carb Keihin CV32 x2

1979 KZ400B
Carb Keihin CV32SS x2


1980 KZ440 Belt
Carb Keihin CV36 x2

1981 KZ440 LTD
Carb Keihin CV36 x2
S3 Carb CV32