Ok, I know this isnt a quad question, but I know someone out there has to have some ideas that might help. My kx wont start but for maybe every 15th or 20th try. Every time I try to start it, it will fire, then kick the kickstart lever up extremely hard. I have no clue as to what it is doing. Could someone please help, i need to get this thing running and sold soon. Oh ya, it fouls plugs easily.

 

It sounds like your timing is off, firing early. You can track it down yourself. I would take it to a mechanic.

 

First pull your reeds, inspect them, make sure thiers no cracks and they lay flat (new boyson reeds $25)
Then check your timing, bring the fly wheel to the top dead center mark and see if the piston is at top dead center (this will check if the fly wheel key has sheered, I doubt it though)
Then check your points gap, also inspect your points for pitting or round edges (also about $25)
If you do these three things you will find your problem.
Don't pry your fly wheel off, use a fly wheel puller for bikes, you may damage your stator other wise.
Your problem isn't a big one and is worth bringing to a shop, if you don't feel comfortable trying these test.
I would put money on the reeds or the points, but nothing is that garranteed!
Good luck!!!!!!!!