A couple common problems on the YT's are sheared flywheel key (usually will jerk your arm back when trying to start though) or faulty ignition coil. The coils on these like to crack on the plastic body, and arc over to the frame. Try starting it with the fenders removed, and see if you can see spark jumping from the coil when you also have the spark plug grounded. If it looks ok, try unplugging the kill switch at the connector, then try to start. That rules out kill switch problem. Otherwise, try a little starting fluid down the plug hole, and see if it pops. If so, you have a fuel issue. I know if you need a new coil one from ALL the yamaha 3 wheelers from a 60 to 250 will work perfectly. Even the 4 stroke 200 and 225's will work. Hope I gave you an idea. ---- 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