I recently purchased an older Kawasaki enduro, how do I find the year and model? The bike didn't come with a set of keys because the previous owner lost them over the years, do I have to replace the ignition switch or can I jus order a replacement key?

The WR and the OR 390 and 400 required a lighting kit to be purchased as an accessory to be fitted for Enduro/ street legal use. Honestly I would try to find a Chilton's manual for those years, browse thru see if it has what you need before you buy it.
Also quite often they're Online sites & forums dedicated to various manufacturer's.
Husky's (aside from left side kick starting)
are awesome bikes, I am sure the is a HUSKY forum somewhere out there, the older the forum the more information is usually in previous posts or the search engine.

check the ignition fuse its blown. put a new one and it wil start

I suggest you discuss this matter with the parts guy at your Yamaha dealership.

Try Cornwall Kawasaki's website and go onto parts diagram for your model and year, good exploded views.

You didn't say what year model, but really not much has changed on the GPX over the years. Which makes this engine swap a snap. You can try ebay for a used engine or possibly someone parting out a bike. Also, a company called Factory Powerhouse, they sell bolt in (pit bike) engines.
Here is the link, i hope this helps.

http://www.factorypowerhouse.com/Pit-Bike-Engines-s/50.htm

You didn't say what year model or size of your bike, but most have a neutral safety switch and a side kickstand safety switch. When you dropped it, it probably effected the operation of the switch.

You didn't say exactly what your bike is, year, model and engine size. Go to the site below and you can see an exploded view of the carb. www.babbittsonline.com

You haven't said what model or year of kawasaki.

Some newer bikes aren't supposed to be jump started. Take the battery off the bike, replace the fuse, charge the battery on a proper charger overnight (as opposed to a battery conditioner like optimate). It should now start fine and not blow the fuse.

If that doesn't sort it, the dealer will need to reset something.

If your bike is a four stroke, the problem is either carbs out of balance or, more likely, the valves need to be re-seated. You didn't say what year, model, or engine size in your posting.

could be the wiring in australia they came with an extra loom to run the bike with out a key ignition switch, the previous owner may have changed them and not changed them back