As DrainFade and I work on our motorcycles, we have been putting together guides to help others.

Kawasaki Ninja EX250R
Valve Check and Adjustment A step-by-step guide to checking your valves and adjusting them. Also included is cleaning and gapping your spark plugs and synchronizing your carburetors. A short version of this guide is available.
Carburetor Check and Synchronization A step-by-step guide to checking your checking and synchronizing your carburetors. A short version of this guide is available.