1980 Suzuki gs450 no spark at plugs, stuck, i need your help

this bike has no spark at plugs, new 12 volt battery, supposedly good CDI off Ebay, , seems to b stuck , i poured oil down cylinders n it rotates maybe 180 degrees, then stuck, i'm thinking coils from 1980 r worn out , headlight horn signals , taillight , neutral n gear lights all function,, have not adjusted clutch ,have not tested ignition pickups...r there upgrades to the coils u reccomend? what can i do 4 the stuck issue, why does bike not have spark?