Z650B1 VM24SS Bench Synch Problem

Hi, this is probably me being dumb, but hopefully someone can help.....

Z650B1 UK model with VM24SS carbs. No weird accelerator pumps or anything, and the version with air screws at the back not pilot jets under the bowls. I've stripped down and cleaned the carbs, and reassembled them with lots of nice new bits. Next step is bench synchronisation before I put them back on the bike, and this is where I'm getting confused.

First off, can I confirm I should be putting the wire in the back (airbox) end, and that the front (engine) end is where the notch on the slides should face ?

Assuming that's right, the problem is that the slides won't close fully; if I adjust them down as far as they go, there's a gap of around 4-5mm, not the 0.5-1mm that I should be aiming to slide a wire in. I'm not using any real force, so I'm not tightening the slides down hard, but it feels like they are bottoming out.  The needle clips are on the standard 4th slot from the top, and the knurled idle adjuster screw is in and adjusted to give me about 1.5-2mm space at the bracket.

What have I put back wrong that it would do this ?  All help gratefully appreciated !

You should be measuring at the notch on the downstream side.  I don't have the book in front of me but the gap should be around 0.7 mm.

The cutaway should face the air box. That is it inlet side of the carbs. Outlet is the engine side. You bench sync from the inlet side.

www.kzrider.com/modules/ServiceManuals/K...Service%20Manual.pdf

It doesn't matter how much slide spacing you have as long as they are all the same.  After sync, lower the slides using the main throttle stop.  

As Nessism said, it doesn't really matter as long as all are the same BUT ensure your idle screw is set roughly mid point so as to allow you to lower all four slides to the closed position. 

After quickly setting the gap on 1 carburetor, I used 2 identical drill bits to set the other three. easy.
I removed the throttle return spring while doing the job so that the slides wouldn't get buggered.
Adjust the idle after starting the engine. Then do the fine synchronization using a carb sync vac gauge set.

VM24 carburetors w accel pump. your throttle slides should be oriented the same.



 

Thank you everyone for the replies !

I found I had to work from the engine side of the carbs, there's no way the cutaway on the airbox side will get close to closing enough. But I've ended up with all four the same.

In the process, I discovered an interesting thing I hadn't spotted before; the adjuster screws come in two lengths. I must have done a swap around at some point, because when I checked, the set I'm working on had three long and one short adjuster, and one of the spare sets had three short and one long. It's only a matter of a couple of millimetres, but until I swapped it back they just wouldn't sync right.

 

It is my understanding that the slide that came stock on the B1 models with only a pilot screw, not an air screw or both has a cutaway of 1.5 which does face the air intake side.  It does not have a notch on the bottom of the slide on the engine side as some the later sets of carbs do.  IMO you were correct to check it from the engine side.