99 kawasaki ninja carburator proble...lose of power between 5-8k

[Rockstar6r]

Like title said. I have a bone stock 99 ninja zx6r. The bike runs okay unitl around 5 thousand rpm's and then it kind of just holds itself back. If i keep the throttle pinned the bike will work its way slowly through it unitl it hits a round 8k and then its all fine. I took the carbs off to clean them thinking that they may just be gummed up but no help. Maybe carb are out of balanced ??? Also, if from a dead stop a snap a big rev the bike jsut stalls. I have to chuck 3-4 revs slowly to bring the rpms up

[richw]

Weird and in Jive

Where is power during the rev range. If it hasn't been looed at I would go through the usual stuff including plugs and look for vacuum leaks and if any ignition sensor TPS on the carbs is plugged in

Also is there a exhaust valve etc and is it operating at all or cables screwed etc.

[stoinkythepig]

Might be ignition related. I had a bike with a partially failed ignition module. It was stuck at a single timing setting (would not retard or advance) and made no power to speak of until it got above 4000 RPM. The bike started fine, and idled fine. The modules are typically the same over a broad range of years, and they are really easy to swap, so perhaps you could borrow one for a brief ride and see if the problem goes away. www.buykawasaki.com has parts diagrams and part numbers, you can X-ref the 99 ZX6R with other years to see what years will fit.

[Rockstar6r]

Ill check the ignition modul for sure. I took the carbs off and thoroughloy clean ed them but not sure how to check for vacume leaks??? Could this be jet related at all ???

[richw]

depends if they are rubber mounted then can leak like crazy if rubber cracks

I have had success filling cracks with black silicone seal

[ZoomSplat]

I'm on a zx6 forum, and someone had this same problem...He never updated us with what he found, and now I can't seem to find the thread to link you to...

Funny, there's a "rockstar6r" on that forum too.... Hello! (the wonders of the internet)

Kind of a pointless post, I guess. Sorry.

[kbroderick]

I don't know about the ZX6R, but the Ninjette runs lean from the factory in that rev range to meet EPA requirements. Perhaps that's part of the equation (if it's lean to begin with, it could be more susceptible to other issues)?

[ChicknStripEatr]

I have the exact same bike, a few years back, something similar to this drove me nuts trying to diagnose. Turns out the negative terminal on the battery was loose enough that the vibration in that range would cause terminal wiggle just enough so that it would arc. Doesn't hurt to check all posibilities.

[Rockstar6r]

zoom splat that me on the other forum. lol. ill try that battery terminla tomorow. Couldnt hurt. Its just such an annoying problem and no body seems to know how to diagnos it

[scootertrash]

One more possible thing to check...
I have a 99 ZX9R which had a very similar problem. On the back side of the carbs on my bike (toward the rear of the bike) there are short metal tubes, maybe an inch long. I believe they are used when you sync the carbs with a mercury stick. There should be rubber caps on them. On one of mine, the rubber cap had a split in it from dry rot. I bought a set of vacuum caps from my local autozone and put new ones on. Problem solved.
I assume the ZX6R carbs are similar to ZX9R carbs of the same year, but I am not sure.

[Rambunctous]

To find a vacuum leak take a spray bottle with water and spray around suspected area and if the idle slows down "presto" you found it.

[butcher bergs]

I disagree with spraying water into your engine.

Ether (starting fluid) or WD-40 will work for finding leaks.

FWIW, I used ether to literally pinpoint the intake leak on my truck....no guessing whatsoever.

[ZoomSplat]

+1, don't use water. Use a can of starter fluid or brake clean. The idle will pick up instead of dying down, but you're spraying a flammable substance instead of water, so there's no harm.

[richw]

Propane from an unlite torch and motor speeds up