You can just order one up from www.mrcycles.com or any number of online Kawasaki dealers.
It costs $256. It is an Electrofused cylinder and cannot be bored, but you can put a sleeve in it. Your local machine shop can order a sleeve from LA Sleeve and install it for you. You will probably save about $70 if you sleeve it.
Being it's a two stroke, be sure to check the crank seals and rotary valve o-rings before you spend big money on the top end. Replacing any worn parts now will save you doing the job twice!
