This will help you identify year. It is from yamahaenduro.com site.
Great forum and great members, as our own...
so i just got ahold of a 69 or 70 or 71 ct1 175 yamaha enduro. I am man enough to admit i have no idea what im doing with this thing. I kicked it and i had spark. sprayed it with ether and she ran...kinda. Decided to play with it again, and no spark. I literally did nothing to it and it lost spark. played with the chopped up wiring and spark came back. Then she pulled a Houdini on me, but this time spark never came back. So anybody got one of these things. Any body got any ideas on what might be up. I think it might be a short but im lost. im taking any thoughts other than my own. thanks
Check all grounds. Also is it CDI or points?
sorry for the delay. its a points style ignition. it has CT1 stamped on the head and the jug has 172cc on it. i have never set points on anything. ever. so im just shooting at shadows.
I read to go 1.8 mm btdc and gap it at .03mm but i have better luck just eyeballing it.
when i gap it to the "correct" position the spark comes and goes on every couple of kicks. when i set it up by eye it stays sparking everytime. i can get it to backfire on me occasionally now but before i had it running.
i know the carb needs to have some stuff replaced in it but it would run on ether. now it wont run at all except a backfire now and again.