Throttle slides

Can throttle slides from a B4 KZ750 be used in B3 carbs? The cutouts and possibly the needles are different.

According to Partzilla, B3 and B4 slides are the same part number.  

www.partzilla.com/product/kawasaki/16059...14b8febfeb17e499cb4c

I'm asking if the slide on the right can be used in carbs that accept the slide on the left. In spite of the partzilla part numbers they are not the same. The spring and attachments inside the slide are not the question. The cutouts and needles are. Thanks 

I do not know the answer to your question, as I have never tried to do so. I would assume they will, but note there are different part numbers for the carb sets,  From the Kawasaki web site it is indicated that for the B1,B2 and B3 model years the part # is 16001-249. While for the B4 the set # is 16001-1019. Are there any differences between the 2 part#s that would create issues with exchange between the 2 slides and needles?  Again I do not know, but would think there are not.

If you have not as of yet found WGcarbs site this link may help with more info.  www.wgcarbs.com/index.php/using-joomla/e...-categories/93-KZ750
 

What's a "cutout"?  

Looking further at the parts fishe suggests that Kawasaki made a running change on the slide, and related hardware.  The various piece parts don't seem to interchange.  The parts fishe suggests that an entire assembly would interchange, but that seems unlikely.  If you need a spare slide, with ancillary parts, I'd look for a complete assembly

The bottom of the slide is not flat. The part that's missing is the cutout. It looks like Kawasaki changed the slide during the '79 model year. The cutout is different from the '78. Just trying to figure it all out. 
Z.