timing question?

[rugabugadouglas]

i have a 79 110 and i recently rebuilt the motor. when i put the cam back in it started up finethen i jumped 180 deg so i put it back on time started fine. kreemed the tank so i can ride with out leaky gas started ran funny so did some carb adjustment died wouldnt start 180 deg off again!!! so i put it back on time pulled it over wouldnt start check timing again 180 deg off. what would my prob be? bad chain? am i putting the cam in wrong? i put it in lobes down and then spin it up to line the holes up. is the gear in backwards? any help would make me happy

[jason 32]

are you sure the cam jumped time?? or did the advancer on the cam jump time -
i had this problem with my 200x-- pissed me off too- the bolt that holds it on needs a washer to keep it in place-
put the cam back in time it then make sure that this part doesnt slide out of the housing ----