GPZ Carbs on a GS?

[srsupertrap]

Does anyone has any experience with running 81-84 GPZ750 Carbs on GS1000 2V. First question is the carb spacing the same? I ask because I am considering CV Carbs for a GS1100 2V project; I have ruled out the GSXr Carbs because the vast majority of 36mm Carbs and above are bigger than the theoretical optimal carb size of 32.6 to 33mm. I have also found out the GSXr Carb emulsion tubes wear quickly. Strike 3

I believe the 80-83 KZ750 may have had 32mm CV Carbs but f you have some background and information I am all ears.

TIA

 

[7981GS]

The CV carbs on my '84 GPZ750 are in fact 32mm.
Why not just get a set of 34's that came stock on all '80-up 1000's?
I have seen adapter manifolds for the early heads if this is for your '79.

Daniel

 

[Nessism]

Or what about the 1150 36mm CV's? Should be plenty for a 2V 1085cc engine.

 

[dardoonk]

Carbs carb spacing on a GS750 is listed at 77-93-77. The spacing on KZ750/900/100 is also 77-93-77, thus a fit

All Kawasaki Z1, KZ900, KZ1000, KZ1100, GS750 & GS1000 all share the same spacing

Jetting and setup most of the difference. Most Suzuki carbs run much leaner on main jet, fatter on pilot and a different slide cutaway (leaner). Currently running BS34 on my KZ1100 with a Wiseco 1166 kit and had no problems outside of the choke configuration being different.

 

[srsupertrap]

Or what about the 1150 36mm CV's? Should be plenty for a 2V 1085cc engine.

I have read the 1150 36mm CV are an excellent choice for modified GS1100 4V. They might be large for a 1085cc 2V at my mile high Denver altitude. I was thinking smaller CV Carbs for the GS1100G head to maintain snappier throttle response.

Just brainstorming . . . .

 

[srsupertrap]

Carbs carb spacing on a GS750 is listed at 77-93-77. The spacing on KZ750/900/100 is also 77-93-77, thus a fit

All Kawasaki Z1, KZ900, KZ1000, KZ1100, GS750 & GS1000 all share the same spacing

Jetting and setup most of the difference. Most Suzuki carbs run much leaner on main jet, fatter on pilot and a different slide cutaway (leaner). Currently running BS34 on my KZ1100 with a Wiseco 1166 kit and had no problems outside of the choke configuration being different.

Dardoonk,
The GS1000 is also spaced 77-93-77mm as well. I have no experience with CV Carbs, do you happen to know whether the GPZ needles are adjustable or do you need a jet kit with new jet needles to juggle clip positions. I think the stock GS BS34 needles are non adjustable but not sure

Thanks for the information

 

[Nessism]

I have read the 1150 36mm CV are an excellent choice for modified GS1100 4V. They might be large for a 1085cc 2V at my mile high Denver altitude. I was thinking smaller CV Carbs for the GS1100G head to maintain snappier throttle response.

Just brainstorming . . . .

Hey Steve,
A set of 34mm CV's are easy enough to find, as are the intake boots. Simple bolt on. I wouldn't go down to 32's though, even from the factory they used 34's. And don't be fooled into thinking CV carb throat diameters compare to slide carb throats, because they don't - CV's have the butterfly in the airflow which restricts them.

 

[srsupertrap]

Hey Steve,
A set of 34mm CV's are easy enough to find, as are the intake boots. Simple bolt on. I wouldn't go down to 32's though, even from the factory they used 34's. And don't be fooled into thinking CV carb throat diameters compare to slide carb throats, because they don't - CV's have the butterfly in the airflow which restricts them.

Ed,
Good point . . . I know Tkent02 has several sets of BS34 CV's floating around his garage. I will have to investigate when he is back in town.

 

[dardoonk]

Dardoonk,
The GS1000 is also spaced 77-93-77mm as well. I have no experience with CV Carbs, do you happen to know whether the GPZ needles are adjustable or do you need a jet kit with new jet needles to juggle clip positions. I think the stock GS BS34 needles are non adjustable but not sure

Thanks for the information

My carbs are from a GS and you are correct, not adjustable. I did need to raise them while tuning my KZ, so I just flipped the the little thing-a-jig (sorry the technical brain lock) on the needles over when I pulled them apart. That raised them enough for me.
I can't comment from experience on the KZ carbs because mine was originally fuel injected, but I'll tell you what I know. However, my factory manual provides a needle clip position for various bikes and does list US models as having this. However, in the "Considerations for Racing" section of my manual, they indicate US models do not have adjustable needles.

To throw another wrench at you, Kawasaki used both 32 & 34mm carbs on their 750 and in conversation with a dealer here last summer, they were unable tell me specifically that all GPZ750 did in fact run 34mm carbs (most did). It appears it was dependent on the camshaft, which changed in 82. To my knowledge, all KZ750's did have 32mm carbs, though.

Another consideration you is that there were other differences in the BS34 carbs used by Kawi on the 750 & the larger bikes.

Main Air Jet 250: Pilot Air Jet 300: All 750 Models
Main Air Jet 85: Pilot Air Jet 350: All 1000/1100 Models

I don't know how these compare to the Air Jets used on GS models, but I think you'll need to check this before slapping on the GPZ750 carbs as I would expect the air jets on those carbs to be different again.

I am curious to see where you end up on this.

 

[robbiem1961]

kawasaki gt 750 carbs

kawasaki gt 750 carbs

hello my mate; way back in the late 90s a mechanic friend; with a bit of work; fitted a bank of kawasaki gt 750 carbs to my old gs 850; he had only to raise the needle one groove and she ran sweet as a nut; bang on the nail; we had to use triumph T140 inlet manifold boots in the carb/head join up; he had to machine new inlet manifold spigots to accept the new boots; the boots were a fraction too long and the airbox rode at a slight angle; noticeable; but i could live with it we also had to replace the automatic cam chain tensioner with a manual type as it fouled the carburetors; we found it possible on the 850 with some compromises, i would imagine that the 1000 would be a very similar proposition;
Be of great joy and of much cheer;

 

[Steve]

Robbiem1961, it's nice to see you join in and offer your thoughts, but did you realize that you were making suggestions to a thread that will be four years old tomorrow?

I'm sure the information is still valid and welcome, just wanted you to be aware.

.

 

[49er]

Very valid point Steve. I was reading the earlier posts too but hadn't noticed the age of the original enquiry.

Prior to Robbiem1961's post, I was wondering why Mrsupertrap was suddenly looking at CV carbs when I remember him buying a set of RS34's not too long ago!

Another Lazarus!

 

[robbiem1961]

hello again my friend; i did realise the age of the thread; but as one person had asked the question; then someone else will probably ask it also; i find myself perusing gs650 threads just because they're there; weather today is very sunny and bright; but the ground is still frozen hard;