Right up under the tank.
It has 2 plugs NGK D9EA
2
if u look on top of the cylinder it should be there
There are two, you will need to remove the tank to reach them on top of the cylinder head cover.
Kawasaki stopped making the ZX9 in 2003. If it is any other year you have to take the gas tank off & the air box to access the plugs.
Anyplace that sells spark plugs will have an application chart which will tell you what plugs will work in your Kawasaki.
two = )
Ngk d9ea
it depends on the number of cylinders.. if 2 cylinders it has 2 spark plugs if 4 then it has 4.
The Spark plugs on the Ex250 are under the fuel tank, to change them, you'll need to remove it.
there are two on the 650 and 750 models from kawasaki
Take off the fenders, then remove the gas tank. You will see the spark plug wires right there on top of the engine, remove those and voila!