Top carb sync screw "position" reference needed..

Hey everyone,

Rebuilt a set of used carbs and plopped em on my running GPz550 so that I can take my stock ones off and rebuild those and get them sent off for cleaning and painting..

The ones that I got used came off a running bike and everything on them is perfect.

I think I am having an issue getting them to sync up properly and looking at the top sync screws Ive noticed that they are all in different postions. Is there a universal starting point for these? Like the general 1 3/8 turns out on the air screw?

My battery died on me so I have to get my charger.. i got it to run but two carbs were way off compared to the others and after an adjustment (very slight) my battery died.. just wanted to get a rough starting point for those top screws.

Thanks!

I guess Ill yank the carbs out to verify the slide positions.. I didnt even do that before I put the bike in which is why I was asking about a general question.. kinda having a brain fart day. :silly:

There is no standard starting position for the sync screws. They are used to make adjustments to the slide height, and most likely they will all be different to some degree. If the carbs are way out of sync you can bench sync them using the wire method first, but if you bench sync them you will still need to sync them using synch gauges or sync tool after installing them on the bike to fine tune them. Both sync methods are described in the Kawasaki Service Manual. Ed

According to the book I need .5 to 1.0 mm between the valve and the bore.. problem is when I use the sync screws to set this, I cant tighten the lock nut down because the sync screw is up about a 1 1/4" turn too high

There is no general position for the synch screw on each carb. If any are way out in one direction or the other, that may have been due to a vacuum leak on the previous motor the carbs are from. If you are using a box-end wrench, you should be able to snug up the locknut while holding the set screw from turning with a screwdriver. It doesn't need to be super tight.

There's a bunch of manuals and other important KZ550 info in my signature you may want to look through.

Could the problem be related to the position of the throttle stop screw when you are setting the slides' heights? Ed

The problem is the nut is all the way down, thus stopping against the larger set of threads on the lower part of the screw.. Theres no way for me to get the slides open .5 - 1.0 mm's.. more like .3 - .5 at the most..

I have the haynes, kawasaki and clymer and i seem to be stuck with all three..

my old set of working (albeit needing tuning) carbs are at the ultrasonic cleaners and im pretty sure hes ripped them apart.

Correct me if I have the procedure wrong.

-undo idle screw, then screw in until it touches, then 1/4 turn more

-adjust slides/sync screw to .5-1.0mm of space between bottom of the float and bottom of carb bore


Should I use the idle screw to get the .5 - 1.0mm clearance?

The wide open throttle stop screw? or do you mean the idle?

I don't know what carbs your bike has, but the procedure is different than mine (I have VM24-SS carbs). If you can post the carb type maybe someone with those same type carbs can provide better insight. Ed

TK22.. ive seen loudhvx's pages and theyre wonderful.. but maybe i just need a day to dwell on it.

Driggs wrote: ...Correct me if I have the procedure wrong.

-undo idle screw, then screw in until it touches, then 1/4 turn more

-adjust slides/sync screw to .5-1.0mm of space between bottom of the float and bottom of carb bore


Should I use the idle screw to get the .5 - 1.0mm clearance?

The floats have nothing to do with setting the slide height. I think you meant "slide".

You don't usually have to mess with the idle screw, (that's the big knob in the middle of the rack), to set the slides equal by eyeball. You can just hold the carbs up to a light and see the sliver of light coming through. Just match all four to the same sliver.

The throttle stop screw is one of the small set screws near the #1 carb. It is the one closest to the outlet of the carbs. The one further away from the outlet is the fast-idle set screw.

If the setscrew is out to where the locknut no longer tightens against the belcrank, then the setscrew is too far out. The slide is all the way maxed out upward before the setscrew comes out that far. Set all four to the middle of their operating range before trying to bench sync.

If for some reason, that one slide is all the way down, even though the setscrew is all they way up (and partially out), then someone may have taken it apart and lost the spring, or put it back together wrong. There is no real reason to ever take apart the adjustment mechanism. It is also very tricky to get it back together correctly. There are several little pieces that all need to go together while spring loaded, and it's easy for the spring to shoot off into space.

You might be able to inspect the mechanism, and compare it to another one, if you remove the throttle return spring and open the throttle all the way.

loudhvx wrote:

Driggs wrote: ...Correct me if I have the procedure wrong.

-undo idle screw, then screw in until it touches, then 1/4 turn more

-adjust slides/sync screw to .5-1.0mm of space between bottom of the float and bottom of carb bore


Should I use the idle screw to get the .5 - 1.0mm clearance?

The floats have nothing to do with setting the slide height. I think you meant "slide".

You don't usually have to mess with the idle screw, (that's the big knob in the middle of the rack), to set the slides equal by eyeball. You can just hold the carbs up to a light and see the sliver of light coming through. Just match all four to the same sliver.

The throttle stop screw is one of the small set screws near the #1 carb. It is the one closest to the outlet of the carbs. The one further away from the outlet is the fast-idle set screw.

If the setscrew is out to where the locknut no longer tightens against the belcrank, then the setscrew is too far out. The slide is all the way maxed out upward before the setscrew comes out that far. Set all four to the middle of their operating range before trying to bench sync.

If for some reason, that one slide is all the way down, even though the setscrew is all they way up (and partially out), then someone may have taken it apart and lost the spring, or put it back together wrong. There is no real reason to ever take apart the adjustment mechanism. It is also very tricky to get it back together correctly. There are several little pieces that all need to go together while spring loaded, and it's easy for the spring to shoot off into space.

You might be able to inspect the mechanism, and compare it to another one, if you remove the throttle return spring and open the throttle all the way.

I meant the slide not the float :whistle: :side:

I for whatever reason was thinking i needed to adjust the slides on the intake side and not the engine side.. thats where I ran into my problem.. DOH.