I had the same problem on my 200x, I rode it one day it was fine, and then just up and wouldnt start the next. I ohm'd out my ignition coil, and got a scetchy reading, but checked fine one test, then I'd try it again and got somthing completely opposite. I replaced it with a different coil I had laying around, and it fired up in the first pull! You can also ohm out a CDI, you will have to look at the manual, because it tells you to go from specific post to post after you have it unplugged. Good luck, and hope I helped a little. ------- Jon.
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