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I would still check the timing advance unit making sure the advance weights and springs are functioning properly. I know earlier you indicated the it was non adjustable but I believe the KZ1000P used the old style mechanical advance unit until Kawasaki stopped making the model in 2005.

baldy110 wrote: I would still check the timing advance unit making sure the advance weights and springs are functioning properly. I know earlier you indicated the it was non adjustable but I believe the KZ1000P used the old style mechanical advance unit until Kawasaki stopped making the model in 2005.

Yeah, it does use a mechanical advance with pickup coils. It's non-adjustable in that you can't rotate the plate, it only screws on at one angle. Lubing that sucker up was the first thing I did when I got the bike. I also pinched the springs a bit so the weights are firmly pressed against the rotor when at rest. None of that made any difference though.

I too had a really bad flat spot just as I would transition from idle to throttle, it would cough and miss. My engine is the Gpz1100 with a bunch of mods including a set of Mikuni RS36 carbs. I tried different carbs, exhausts, air filters, ect. No matter how I tried to tune around the flat spot it remained. Fought it for several years and simply learned to ride around it. After much frustration and a bucket full of needles and jets I found the problem. It turned out to be the mechanical advance unit. I had replaced it several times during my trouble shooting but it did not fix the problem so I assumed it was not he issue. I replaced the unit with used ones, they all looked great and appeared to function correctly including the springs.
One day I decided o buy a new one just to see. The new one is still available from Kawasaki and includes new springs. Installed it and my problem went away, the thing carburets smoothly, no hickups or misses. I think it was the new springs that did it but you cannot just buy the springs.

baldy110 wrote: I too had a really bad flat spot just as I would transition from idle to throttle, it would cough and miss. My engine is the Gpz1100 with a bunch of mods including a set of Mikuni RS36 carbs. I tried different carbs, exhausts, air filters, ect. No matter how I tried to tune around the flat spot it remained. Fought it for several years and simply learned to ride around it. After much frustration and a bucket full of needles and jets I found the problem. It turned out to be the mechanical advance unit. I had replaced it several times during my trouble shooting but it did not fix the problem so I assumed it was not he issue. I replaced the unit with used ones, they all looked great and appeared to function correctly including the springs.
One day I decided o buy a new one just to see. The new one is still available from Kawasaki and includes new springs. Installed it and my problem went away, the thing carburets smoothly, no hickups or misses. I think it was the new springs that did it but you cannot just buy the springs.

That's interesting. Did you replace the whole unit, plate, coils and all, or just the rotor with the weights/springs on it?

I had already swapped the entire ignition system with a Dyna S including coils and wires, I Just bought the advance unit and swapped the Dyna S rotor onto it, I had my doubts it would fix my problem so I wasn't expecting much but wow it solved my problem. Not saying it will fix yours but you never know especially if you have done everything you can think of. Here is the link to the part, it's $86.83 but was worth it.
www.partzilla.com/parts/detail/kawasaki/KP-21148-1020.html

baldy110 wrote: I had already swapped the entire ignition system with a Dyna S including coils and wires, I Just bought the advance unit and swapped the Dyna S rotor onto it, I had my doubts it would fix my problem so I wasn't expecting much but wow it solved my problem. Not saying it will fix yours but you never know especially if you have done everything you can think of. Here is the link to the part, it's $86.83 but was worth it.
www.partzilla.com/parts/detail/kawasaki/KP-21148-1020.html

Yeah, I've already spent way more than that on the issue.

I guess I'll try switching the rotors between the two bikes and see what happens--should be easy enough. I haven't done that so far because it seemed pointless, and if the springs were going to be stretched out anywhere, I'd have guessed it would be on the old bike (which is the one that runs fine).

Baldy110, thanks so much for pushing me in this direction.

I finally swapped the timing advance rotors between the bikes, and wouldn't you know it, the new bike pulled just like the old one! It changed the behavior of the choke too. Now it'll race if left on full for more than a few seconds (the old bike also did this). The idle didn't change.

I guess I probably pull the carbs again and remove those shims.

Here's the really weird part though. Although swapping the rotors made a very noticeable change in the behavior of the new bike, it didn't seem to affect the old bike much at all. It lowered the idle a tad and maybe there's a slight hesitation off idle? I can't really feel it. Now both bikes are pulling like rockets.

I have no idea what to think of this. Are the springs too tight? Too loose? Is something else different about the mechanisms? They look and feel identical.

People forget to clean 3-4 holes next to throttle edge. They work for first few degrees of throttle opening.
Heat up needle end and bend it. This is tool for cleaning the holes. Try to adjust accelerator pump. Check pump diaphragm.
Sometimes idle jets are partially clogged. I clean them with needle and then check with magnifying glass looking at light.

Do the two rotors have the same numbers? They are not all the same.
Steve

car5car wrote: People forget to clean 3-4 holes next to throttle edge. They work for first few degrees of throttle opening.
Heat up needle end and bend it. This is tool for cleaning the holes. Try to adjust accelerator pump. Check pump diaphragm.
Sometimes idle jets are partially clogged. I clean them with needle and then check with magnifying glass looking at light.

BS34 carbs do not have, accelerator pumps.

Numbers as in part numbers, or numbers as in the timing marks and whatnot printed on it? I don't think there's a part number printed on it and as far as I know the part for both bikes is 21148.

On the spark advance will be some numbers like (005). Others are different. The pins are in different places on the back. They may look the same but they are not.
Steve