VM26 on kz650 + other performance mods

Hey.

as far as I can understand (correct me if I'm wrong), the VM26 from a KZ900/KZ1000 should bolt right on with little to no modifications as long as you use the carb holders from those bikes, and drill out the mounting holes a little(?)

My bike is currently partly disassembled and my only deadline is to get it running before the summer season starts (and I get my certificate). So I'm just playing with the thought of getting some used carbs, and doing a rebuild (does the main and pilot jets from VM24's fit the VM26's? I have some new ones laying around,  107,5 and 110 mains + 17,5 pilots).

My setup is going to be:
- 4-1 exhaust (unknown brand - was on the bike when I got it, if someone could identify it that would be great!)
- Henry abe breadbox airfilter - will be doing a little mod on this one to cancel out the sidewind/water problem.
- *Currently* VM24 carbs

Would the VM26 be a good way to get a little more power out of the engine? And is there any other easy performance mods I should be aware of? I dont feel like opening the engine just yet, as I would like to have it running come summer, and I just did the ZR7S starter clutch/oil pump/pressure release valve swap. Currently the engine seems to be in very good condition and doesn't have any leaks (yet) apart from a little sweating from the cylinders (this is normal on kawasakis as far as I've heard, and shouldn't be a big issue).


The exhaust:

(I know the chainguard is from another bike, I'm thinking about either getting an original one, black plastic, or re-welding this one and painting it).

Bike as it sits now after the starter clutch swap:


And a little bonus just for fun, previous projects (50cc) 



Best regards





 

There is no point in putting vm 26 on a 650 unless you do a big bore (810) conversion.
Vm 26 came as standard on both 900's and 1000's.
So 4 x 26 dia divided by 900 (cc) = 2.36 sq mm per cc. And less on a 1000.
On a 650 4 x 24 dia divided by 650 = 2.76 sq mm per cc. 
So 650's are over carbed anyway so an increase won't give you anything other than mixture headaches. 

VM26's have the same spacing as the 24's and do fit with the use of the matching boots and a slight elogation of the holes inwards to fit the narrower boot bolt spacing of the 650 head.
They do work on the 650 but would be of more use if the engine had some head work etc

Okay guys, thanks for the heads up! I will put that on hold for now as it seems like getting both the required parts and doing the labor would take too much time as of right now.

Regarding the exhaust, does anyone know the make/model? 

Hard to say... except is a left side exit, making it kind of unique. European??

If you are in the uk I would say possibly an alfa.
 

I'm from Norway, so I guess it's european. Could be from all over the world though, the bike has had several owners before me.

Looks alot like that alfa/alpha exhaust, but doesn't have the same "bend" where the header pipes meet the muffler

The only thing I know for sure is that this exhaust doesnt use the standard exhaust "collars". The flange is built into where it mounts to the cylinder.

Looks like an Alpha exhaust system to me but I am not an expert on them.  You do appear to have the longer rear fender that was stock in the EU.  You also appear to have some nice shop tools as well.

Another carb option are the CVK32 carbs from an early Ninja 600 or the ZR7 & ZR7s.
Manifolds and carb boots from the ZR7 are needed.
I followed a tutorial of Pablo's/z650Spirit on the swap.

 

So this is on another level, but fuel injection conversions are pretty accessible nowadays....

As with the majority of the Kawasaki 4 stroke 4 cylinder motors, the KZ650 was designed from the factory to give optimal performance from the parts that were originally supplied with it. As stock it is a high performance motor package. The only way to get more power out of it in stock condition is to make sure it is tuned to the optimal specifications found in the factory service manual.
The key factors involve 1) Compression 2) Spark 3) Fuel 4) Timing
Check the FSM and make sure your engine is producing maximum compression.
Without compression bigger carbs will do nothing but show tuning flaws (see key factors list above)