Hello, I am having a problem with my ninja. I have an 03 zx12. Bike was running normal and then one suddenly one day its not. Heres the problem... If i go in any gear above 5000 RPM it starts to spit and sputter and almost die out (almost as if running off of 2 cylinders.) The bike starts fine, and idles normal. It runs basically normal until 5000 Rpm, then i lose all power and cant do over approximately 75. Or if I am below 5000 if i give it more then 1/2 throttle it will do the same thing. I dont understand how this just happened all of a sudden. Bike has never done this before other then when i needed to replace the voltage regulator and some other part, i dont believe it is this again, because it isnt acting quiet the same. I also run a power commander 3 on the bike, if this makes any difference. With a full muzzy exhaust. ANY HELP OR COMMENTS WILL BE GREATLY APPRECIATED. THANK YOU EVERYONE

 

Sounds like a fuel problem to me, could be bad gas, low fuel pressure dirty carbs etc. I'd start with a carb cleaning and go from there. Since its happening at high revs and high throttle settings I would guess that its not supplying enough fuel or putting in too much, either way thats my guess. If it was a problem with the ignition system it shouldnt matter what the throttle setting is. Let us know how it goes and welcome to KF!

 

dirty carbs sounds right. welcome to KF

 

Then again my jets fell out once and it did the same thing, but that was a one in a million...

 

hahahaha, only on your ride Prom. But yes, fuel related issues would be my guess as well.

 

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