Or at the very least the small ram air pipe pointing forward into the airflow.

Porn. 

Let me guess, you cleaned the regulator plug contacts and the solenoid plug contacts, and battery terminals.

I'm not sure on your bike as I don't have the wiring diagram, but if like a few kawasakis the headlight relay also uses the starter solenoid and a diode to work using voltage drop over each, so if you have poor contacts in the above items then you generate to much of a voltage drop and the headlight relay will not trip and hold on, as its sensitive to voltage.  I chased up a similar fault on z750, that can be found here http://www.bikersoracle.com/zx9/forum/showthread.php?t=17633 It has the relay diagram which I would assume is the same for most kawasakis using the relay box.

 

Do you have a kawasaki front sprocket fitted, as they have rubbers on either side for the chain to rest on, this reduce lots of chain related noises.
I know they're relatively expensive but for noise and vibration reduction there worth it.

Cam chain tensioners can stick with dirt particles in the engine oil, but they can be worked clean if removed and worked with fresh engine oil, which should be done every valve check anyway but most people forget to do.

If you've never removed a cam chain tensioner before its not hard just not much room.
You do not have to drain the oil when removing the timing rotor cover with the bike on the side stand, and even on a paddock stand you'll only lose a few drips so have a cloth under it.
12mm ring spanner, for removing center pressure bolt first.
8mm ring spanner for the 2 x mounting bolts.
10mm socket for the timing rotor cover.
17mm ring spanner for timing rotor.


When removing the 12mm bolt be aware its sprung loaded and has a steel rod down the middle of the spring to stop it collapsing under pressure, don't loose them.
Now remover the tensioner body, and before playing with it count how many ratchet teeth are visible, because when you come to refit it you will reset it to 2 teeth less.
Now with your thumb freeing the ratchet lock, work the ratchet mechanism in and out with lot of fresh engine oil till its really smooth.
Reset to 2 clicks less than removed.
Refit the tensioner body, 2 x 8mm bolts.
Refit the tensioner spring, steel rod, and 12mm bolt and washer, this bits a little fiddly.
When its all back in the engine, use the 17mm ring spanner to slowly rotate the crank via the timing rotor bolt in a clockwise direction and listen for the tensioner taking back up the slack with the 2 or more clicks. Now its clean and you know its working, refit timing rotor cover panel.