What you're describing is typical of a lean mixture. The kawasaki DFI is a closed loop system, meaning it doesn't measure O2 levels in the exhaust as a feed back signal and ask the computer to adjust the fuel map. The computer only takes information from the ignition coils for RPM, throttle position sensor to determine power requirements, air temperature sensor which is directly related to mass air and the engine temp sensor to determine if an enriched fuel cycle is required on start up.
Fuel supply presssure is critical and injector cleanliness is really important, especially on a closed loop system. In our automobiles, an open loop system is used. This has the O2 sensor and the fuel maps change based on the O2 feedback. As the injectors get plugged, the computer changes the lambda pulse to compensate for the issue to keep the O2 levels correct. If the fuel pressure changes, the computer adjusts the fuel map to compensate. None of this happens in a closed loop system.
. I don't know how you're managing the ethanol in the fuel either ethanol approved fuel stabilizer or a gauranteed supply of ethanol free fuel. Fuel with ethanol in it is consider stale if more than 8 weeks old. Ethanol loves to bond with water or humidity and then causes all kinds of havoc. I can't stress this enough. Fuel stabilizer available comes in 2 variants. The cheaper version is for ethanol free fuel. The stabilizer which is about 8 times the price is probably rated for ethanol based fuel.
So what to do-
Can you check your fuel pressure first? If it's out of spec, deal with that problem first.
Remove your injectors and take them to an injector service shop. Have them flow tested, then decide if you need to have them cleaned and rebuilt. NOTE- There are pintle filters in the top of the injectors about 1/8" in diameter and about 5/32" long. Even if you use injector cleaner, the crap you loosen up will just plug those pintel filters. There's only one way to deal with injectors. Either total replacement or a professional rebuild. Usually around here in Canada $25-$30 a piece for rebuild.
The throttle position senor could be out of calibration, but not likely. Some people screw around with the setting and really mess things up. There is a way to calibrate it and that info is in the manual. If you do tackle adjusting, make sure you have a really good ohm meter and not the $8 version. If you didn't pay $80 or more for your volt /ohm meter, then don't rely on it for calibrating purposes. Not good enough.
Electrical connections on all of the sensor wiring and injector wiring should be checked for corrosion and dealt with.
I'm betting on either injectors being somewhat plugged or a weak fuel pressure regulator and both would be a result of the ethanol issue and the fact that the bike has been sitting for a while (I'm assuming this because this is the beginning of the riding season for most of us)
Hope this helps,
KB
