Sorry I can't help with the replacement specs for the injectors and as much as I would like to say "just change them out for #12 injectors I can't. The Kawasaki has a closed loop fuel program and you can't just swap out similar sized injectors and have the DFI compensate because it wasn't designed to monitor the CO and adjust the program.
Most injectors can be saved. The biggest problem injectors suffer from is boiling of the fuel after shutdown and this creates varnish which will build up in the injector and cause it to stick. A good soaking in laquer thinner should dissolve the varnish. Tossing the injectors in an ultrasonic cleaner will also help but the best fix is to take them to a fuel injection shop and have them cleaned. The standard charge is about $30 a piece. what you get for $30 is a flow test before and after cleaning, plus new pintle filters replaced in the injector, plus dismantle and ultrasonic cleaning and reassembly.
I'd also be remiss if I didn't talk about ethanol enhanced gas and Phase Separation.
Any ethanol enhanced gasoline more than 6 weeks old is considered stale fuel and should be discarded UNLESS you use a fuel stabilizer specifically designed to help stabilize the ethanol in the fuel Ethanol loves to drink water and at some point will absorb water and phase separate out of the gasoline. Then the water/ethanol will start attacking the metal components in the fuel system causing oxidation. I highly reccommend the use of fuel stabilizer for Ethanol Enhanced Fuels if you only use your bike occasionally
I really like Star Tron Enzyme Fuel Treatment www.starbrite.com/startron it will stabilize fuel for up to 2 years. My Porsche 928 might go out for a drive twice a year. If I didn't put stabilizer in it every time I fuel up, I'd be dealing with issues like you're having. My lawnmower, grass trimmer, chainsaw, snow blower etc. all get fuel stabilizer. A pennies worth of prevention saves a pound worth of repairs.
If i were in your position, I would spend the money and get all of the injectors serviced. If the bad one won't clean up, I'd be surprised. The other thing is the fuel injector service shop will also be able to reccommend a replacement if required, but I suspect a good cleaning will smarten things up nicely.
Good Luck,
KB
