Need help KZ550 wont rev over 5k rpm

Hello everyone! I just recently traded my kz440 for a kz550. When I test rode the bike it could not rev over 5k rpm. So I though it could be just the jetting or simple carb fix, but I was wrong.
the bike has tk carbs with Pod filers and a straight pipe with a baffle.
Heres what I did so far:
Clean the carb jets
shimmed the needle 2 spacers
installed 120 mainjet
adjusted the airscrew so many times
New plugs
valves are good


Im thinking it is the timing advancer but I cleaned that and it moves freely!
I have no idea what else to try, could someone help me please!! I hate the feeling of Buyers remorse when I traded my fine running KZ440 where I did the 2into1 Carb setup

did u notice any improvement with the 120 mains? if so keep going bigger.
i asume that was an increase from a smaller main?
if u are holding the throttle wide open when trying to get above 5000rpm, then u are only useing the mains, not the pilots or needles.
air screws are for cruise only(up to 1/8th throttle.)

You may want to do a search on KZ550 pods. There are 162 postings on the subject. Ed

KZRider718 wrote: ...recently traded my kz440 for a kz550. When I test rode the bike it could not rev over 5k rpm...New plugs
valves are good
...timing advancer...moves freely!....

Is fat blue spark visible on every plug?

Is every cylinder combusting? Test by starting cold engine, allow to run for a few seconds, and then spray water mist on the exhaust headers. Mist will instantly vaporize and sizzle off header from a combusting cylinder. Mist will form water droplets which run down the header from a non-combusting cylinder.

Is the ignition timing correct? What system is fitted? Points; Kaw electronic; Dyna-S? Other?

Good Fortune!

well i went from 92 main to 120 did change nothing but that should be the correct jetting. Thats where i am at thinking its the timing.it is not advancing all the way or something.it has electronic ignition. Ill get a video so you guys can hear for yourself.
yes there is good spark but not "fat" but looks like normal spark to me. Revs up to 5k smoothly but after that it wont go. sounds like theres no gas. Also if i wot it sounds like only 2 cylinders are firing and back firing. when you guys see the video hopefully you can help me diagnose the problem.
I recently got a kz750 and dnt want to work on that until i got this bike situated,

KZRider718 wrote: ...Revs up to 5k smoothly but after that it wont go. sounds like theres no gas. Also if i wot it sounds like only 2 cylinders are firing and back firing....

Fuel starvation?-- Fuel tank vent might be obstructed. Would test run with fuel tank cap ajar (not snapped down) to see whether that makes any difference.

Deteriorated spark plug wires? -- old hard cracked plug wires might be leaking voltage. May test with engine running in the dark while spraying water mist over the coils and plug wires, which sometimes reveals errant sparks.

Hope the reported history is correct as to valve clearances being within specs and that the advancer is functioning properly.

Has a strobe type timing light been used to assure correct ignition timing and actual running performance of the advancer?

Good Fortune!

KZRider718 wrote: ...has electronic ignition....

Which electronic ignition? -- Could make a difference in diagnosis.
I.C. igniter or Dyna-S?



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Some possibilities:

Dyna-S module failure;

I.C. Igniter failure;

Faulty ground from I.C. igniter;

Ignition coil failure at higher rpm;

Intermittent short in wire to coil, or in some other wire in the ignition circuitry;

Weak battery;

Faulty ground to engine from negative battery terminal;

Etc.

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What ignition coils are fitted? -- For example, Dyna coils may have a primary terminal connection (eg., head of the terminal screw) that shorts against a coil mounting spacer.

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Internal fraying of either wire to the coil primary may cause intermittent firing. Even where the wire looks perfectly all right on the outside.

This may sometimes be identified by using an ohmmeter while wiggling and manipulating the wire.



Good Fortune!

Jetting won't cause the type of RPM cutoff you describe.

It's usually electrical. Bad coils or advancer (as you already checked). Did you check the advance with a timing light to make sure it's advancing while running?

It can also be a bad igniter. (all as Patton mentioned)

Pods work just fine on the TK-22 carbs, but 120 mains are too big for a standard KZ550. You want to start with 96 mains and maybe go to 98 or 100. 120 may stop it from revving all the way when warmed up.

But the bike should rev even with stock jetting, so I don't think jetting is the real problem.

Make sure none of your choke plates have become detached from the control lever and are now just sitting in the intake tract and are not moving.

Later, when you get the RPM problem sorted, you will want to get 34 or 37 pilot jets for better running at low throttle positions.

I also suspect two needle clips jump is too much. I would go to the 3rd clip from the top on factory or rebuild kit needles.

When you say valves are good, do you mean you checked them, or adjusted them? If you adjusted them it's possible cam timing could be off. If you only checked them, make sure you read the valve train warning in my signature. It also shows exactly how the cam timing should be.

Have you done a compression check?

wow this is going suck trying to figure it out. i will check everything you guys have suggested. but for i really think its not advancing because when i look at the advancer spinning, it doesnt separate all the way for it to allow to advance after half throttle. i have the kawasaki ignition btw. how do i check and see if the ignitor is bad?