I was looking for that same answer and i haven't gotten it yet. I did the K&N R-0990 replacement + HMF slip on. That thing is moving massive amounts of air and i'd like to do a jet kit. Right now i shimmed it 4 #4 washers and it seams like it's running great. I'll probably end up taking it to a dealer w/ a dyno and have them jet it.
How did I miss this?
When I got my Dynojet kit I put in the needles set to the center.
I used the 100 jet on my bike. With yoshi exhauset and K&N pods. the bike felt VERY flat from 7500 rpm. I ended up with DJ#110 main jets and 38 pilots.
I did the same thing to my air box but never installed it. I like the K&Ns better.They make pulling the carbs and rejetting a 15 minute job.
If it is running to lean -You will have poor acceleration, engine knocks and pings, overheating, engine pops spits or backfires opening and or closing the throttle, Throttle response is not snappy.
If it is running too rich- You will see dark exhaust smoke, rough or lumpy idle, poor performance as the ambient temp goes up, flat throttle response(not crisp) and really poor MPG.
The ninja is set up to be lean at idle and lower rpms, richer in the mid range rpms then leans off again at the higher rpms.
Shimming the needles or changing the jets brings a little more power and torque throughout the ranges, but without changing the sprockets,exhaust & air filter, its kind of a mute point. Your best performance will involve a combination of all these.
I put my stock air box on so i wouldn't be worried if i got into some rain. They key to putting it in or taking it out in as one is to take everything off. I had the rear body pannels off, the tail body, and the rear wheel. I had penty of time so it all went smooth. Me and my ol buddy Wiser got it done!