There is no real "bolt on" kit for the 200x. You are going to have to get creative and make some for it, possibly start from a 400ex, or Warrior nerfs seem plentiful on ebay. You will need to cut the nerf and weld it and bend it to fit the frame. Good luck, and I would love to see a 200x with nerfs, I havnt seen one before!
THE 80's RAGE! Currently owns:
81, 85 Yamaha Tri Moto 125
83 Yamaha Tri Moto 200 x2
82,83 Yamaha Tri Moto 175 project
85 Yamaha Tri Z 250
84 Kawasaki Tecate 250
84 Honda ATC 70
85 Honda ATC 350X
84 Honda ATC 250R
(2) 84 Honda ATC 200x
82, 83 Honda ATC 185s
81 ATC 200
Lots of other parts and bikes