atc 90 died

[jessejamesfredd]

Having problems with my 1978 atc 90 I just fixed it up, I got it back to start on one pull and it would idle even if it was cold, now it ran like a beast for 2 weeks and all of a sudden it started smoking and then it died and it will not start??????

Now for those that would like more info here we go.
I cleaned and rebuilt the carb
I changed the oil
Put some new gas filters on it
New sparkplug properly gaped
Fixed the timing which keeps changing?
New air filter

[Kenny_smallz]

the only thing i can think of is and i've had this problem many times is the points being set just right, the vibration of the bike makes it change so much, i hate it but the smoke problem i don't really know

[rodeofan5656]

the only problem i had with my 90 many years ago was that the idle would always change. youd put it in neutral and it would idle waaaaay up like it was gonna blow. never had a problem like this. maybe the bad timin made somethin blow, or maybe the rings just gave out. that would be possible if the internals are all stock

[jessejamesfredd]

The piston and rings are only about 5 years old, I finally took the whole thing apart and the piston and rings look good no scarring.