1985 ZX600r carb switch on KZ650

That's true, but I had only heard a bout the Air correcting jets at that time and shortly after the CVK32 carbs by others on the group. Both seemed like viable solutions to my problem so I started a new thread and messed communications up abit. But I studied everything and adopted both solutions in the end. My easiest first move was to start with the CVK switch. I have the air correcting jets so I want to try that too. Sorry for any confusion. Wookie58 warned me about starting two threads. And he was right.

rstnick wrote:

82KZ305Belt wrote:

Why do people do this swap? Are the VM24's that much trouble? 

No, the VM22/24 SS carbs work fine.

The CVK carbs are a newer design, half the weight, parts are still available, CV carbs tend to run smoother at all RPMs ("no flat spots").
You can smoothly ride from low RPMs to high in a single gear with no hesitation/flat spot.
It does change the characteristics of the throtle feel; no more throtle by wire, more of a delay feeling, but in a smooth consistant way.



 

So the VM's have flat spots even when running with ducts and airbox? I have heard of the flat spots but usually in the context of pods. But I've only been paying attention to such talk for a few months, since I obtained a bike with VMs so its entirely possible I missed such things. 

I haven't ridden mine far enough to evaluate their performance yet, and they will need rebuilding before I can evaluate them.
 

Thankyou for the information it is all welcome. I  have all the necessary parts ordered and shipped on there way and am following Pablo's Z650Spirit article. I will try to document my swap experience for the group when I am ready.

Yes all the round slide carbs have, a flat spot so to speak even with stock air box, But due to air box and carb settings it is much less noticeable via the seat in the pants so to speak, than it is when the air box has been removed. When the carb is transiting from the pilot circuit to the main there is an increase in air volume and a decrease in its velocity which changes the pressure differential which leans the mix somewhat.  

VM24's are excellent carburetors.  They are reliable and easy to tune.  Parts are not too hard to find.  

CV carbs are fine as well, but I wouldn't be going out of my way to remove VM's for CV's if you already have a clean set of VM's.  The only thing I'd stay clear of are the VM's with the accelerator pump.  Those are more trouble than they are worth.

Thanks alot I appreciate you sharing your knowledge. We have the same bike a 1977KZ650 B1.  Mine is all moded up about 11 years ago and my VM24s are wore out so if Im going to change out the carbs Im going to follow all you gurus as best I can. All the parts are on the way. Im going back to the air box. Easier to jet I think with 4into1 . Thanks again
DustyDeck

My VMs are toast and Im invested in the CVKs now so that's my road. Im interested in the experience on switching them over. Once I get that established I will get some VMs going again. My old VMs were loyal trusted friends on three motorcycles and I want that back. I spend all my time working on this bike and drawing. I appreciate your help.
davevincent.com 

She rides very well with the CVKs.
Carb holders (ZR-7S) need to be put on, and air box boots, holes enlarged in the airbox, so not so easy to swap back and forth.

Mine with CVKs:

 

 

 

 

That's very cool, reassuring infact. Thanks for the pics. I should see a few parts showing up in the mail this week. Carbs will get an Ultrasonic cleaning first. Can I ask you your  jetting. Is it around 45/115 ?  PABLO started with 45/112 but then he moved to a 4into1 so I don't know if he changed the Main again. THANKS again

82KZ305Belt wrote:

Why do people do this swap? Are the VM24's that much trouble? 

The CVK's run like a poor mans fuel injection compared to the stock carbs, but there is nothing wrong with the VM's. The swap will give a bit of a power boost as they flow quite a bit more air, similar to throwing on 29 smooth bores is how I would describe it. 

Thanks A Lot, I used to have a set of 29mm smoothbores so that's cool

Nessism wrote:

VM24's are excellent carburetors.  They are reliable and easy to tune.  Parts are not too hard to find.  

CV carbs are fine as well, but I wouldn't be going out of my way to remove VM's for CV's if you already have a clean set of VM's.  The only thing I'd stay clear of are the VM's with the accelerator pump.  Those are more trouble than they are worth.

 

Oh yay, lucky me, that's what I have. 

Edit: looks like the actuator can just be disconnected, hopefully that eliminates any troubles from the pump if it isn't used?