I can already tell you are are running way too lean with that setup. Get a PCIII ASAP and get it custom tuned on a dyno at a shop. You will do some damage long term if you keep riding around like that.
Ok I will tell you how to get to the plugs.
1) The lower portion of the airbox has a 10mm screw at the top towards the steering stem. Remove that.
2) Next... The back left side of the lower half of the airbox has a crankcase vent tube and an oil catch tube on the left side. Detach both of these. Slide the clamps down a little to slide the hoses off. It will be difficult so I use something to pry the tube off to break the airtight seal.
3) Pull up on the lower portion of the airbox to slide the velocity stacks off the throttle bodies. This might be hard to do if this is the first time taking it off. Just so you know the lower half is held on by the velocity stack collars slipping over the throttle bodies.
4) When you finally pop that lower air box portion off there is a reed valve hose that connects to the right side of the airbox on the bottom. Take this off as well.
5) Now that you have the air box off you will see the valve cover with each individual coil for the spark plugs. You may need to temporarily disconnect the T-fitting and reed valve assembly to leave room to work on getting the coils out.
6) Disconnect the stick coils and pull them out. Remember the orientation for each stick coil and how it was positioned on the valve cover. Draw it out if you have to.
7) Take out the spark plugs using a suitable spark plug socket and extension.
8) You may want to check the gap on your new plugs even if they tell you they are pre-gapped. The service manual states between 0.7mm - 0.8mm or 0.028in - 0.032in for the 2008 ZX6R.
9) Remember when you get your new spark plugs apply a small amount of anti sieze compound on the threads. This will ease removal in the future.
10) Using the spark plug socket and extension place them in each cylinder gently and fingertighten until it stops turning. Take a rachet and tighten to a 1/8 turn but no more than that!!
Install everything back todether in reverse and in case you fucked up I have some service codes for you:
#51 = Stick coil cylinder 1
#52 = Stick coil cylinder 2
#53 = Stick coil cylinder 3
#54 = Stick coil cylinder 4
Why would you gut the cat before getting a PCIII and especially without getting a more free flowing air filter?
