TOPIC:

I have an '80 kz1000 that has had some work done on it. Im not sure if the carbs are stock and not sure how to see what size they are. They are mikuni's. Do you measure the width of the engine side of the carb or the filter side of the carb to find the mm size. Also what jets are stock. These have: main jet-140, pilot jet-15 and that is all i could find number wise on the inside. The clip is set at 2 from the bottom. Bike starts then that is all. Touch gas, bogs and stalls.

Post edited by: yellowbike, at: 2007/04/16 20:52

You measure the I.D. of the ENGINE side of the carbs opening,yes.You probably have 28mm carbs

That main jet sounds pretty fat,if You ask Me(140)...I would think a 120-130 max would be sufficient.
And with the clip being at the #2 position,that's also going to richen the midrange.Normally,that clip should be in the middle position(3rd from either the top or bottom,as there are 5 positions)
What are Your air/fuel mixture screws set at?Those You will find on the outside of the carb.Those SHOULD be set at around 1.5-2 turns OUT,once they are seated,but don't tighten them...just snug them closed,and then back them out.They might have caps(plugs) over them also.
If the screws are on the engine side(of the carb body),then they will control the FUEL mixture...if they're on the air-box side,then they control the AIR mixture.In other words,if the screws ARE on the engine side,by turning the screws out,You are feeding more FUEL.

Have You synchronized the carbs?
Have You had the carbs apart?
Done a compression test?
Have You checked the valve adjustment?
Do You have a manual for that bike?

GEEZ...where are Mu MANNERS?!!
Welcome to KZrider!

Post edited by: Sandy, at: 2007/04/16 22:57

Welcome yb,
Only reason I can think of for having a #140 main jet is that someone installed the Dynajet Stage 3 jet kit. Describe your airbox set up and pipes please.

We will also need to figure out which carbs are on the bike... you didn't even mention what type KZ1000. They use different carbs. State your bike model please.

There is also a code stamped on the flange of the carb where it inserts into the bracket that holds all four carbs. Look at the mark behind the choke and on the flange. This is called an ID mark. There is a mark on the other end but it will not be the same, most likely. In any case, will the ID mark, I might be able to take a guess as to which type carb assy you have and help with a rejetting. Yours is VERY likely not appropriate.

pods, 4 into1 vance/hines, i believe b4, the screws are set at 1.5 turns (i have never touched these, til now to check) all four were the same, 120 over 2 is on the flange, screws on air box side.

I think the ID mark should be 1205 not 1202... numbers are a bit hard to read as they are small and shallow. I might have recorded the ID mark wrong. First the OEM specs:

#102.5 mains, 5CN29 jet needles which DO NOT have clip slots for adjustment, 0-4 needle jet, cutaway 2.0, #15 pilot and air screws 1 1/4 turns out.

The #140 mains and skinny, not very tapered jet needles you are using mean somebody has installed a Dynajet Stage 3 kit. The bike will NEVER run right with that kit in there. They use the same jet needle for the 0-4 needle jet it seats in as they do on the VM24s, VM24s and Z1 carbs... Bound to be rich and the main jet is bound to be rich. The pilot circuit may be OK with the pump... they use that jet needle for every thing from 0-2 needle jets to P-6 needle jets... a range of 14 sizes. Wonder why it doesn't work well with most of them? The ol' one size fits all issue...

I would find some of the 5CN29 jet needles, put in #120 mains and #17.5 pilots. That should help quite a bit. Those carbs respond well to being converted to non-accelerator pump with the proper rejetting and will actually be less fussy to tune and will not have the complication of the accelerator pump... note the number of "my pump doesn't work" posts in this forum.

Is it hard to convert to non-accelerator pump? Thanks for all the info on the carbs.

Try posting a photo or two. It should help clear things right up.

The easiest way to tell the 26's and 28's apart is the VM 26 has a thicker wall on the spigot (where it mounts to the engine).
This is a 26mm.

This is a 28. It has a thinner wall on the spigot than the 26mm carbs (above).

Not really hard. You just have to have another set of bowls and the know-how to rejet. The stock jetting on the 28 pumpers is pretty lean to begin with. The pump is there as a crutch (shoots ONE shot of gas into the combustion chamber on the off-idle throttle turn) so the bike won't backfire and surge. Fish is correct regarding his way of identing the 28 vs 26 carbs... you can also bet all the 26s on a Kaw with an accelerator pump will have TWO fuel inlets. The 28s have one.

Post edited by: wiredgeorge, at: 2007/04/18 08:11

do i have to get 4 new bowls or just the one with the acc. pump on it? i have 26mm carbs

pic of bike on site. says wish would stay running. thanks for the help so far with this