Single cams I think mate.
One is 1980 model, one 1985, another one looks same but ID tag is gone so cant get exact year. Those 3 bikes all have exhaust port on right side of the head and have round steel swingarms. The 4th bike is I think tag says 1983 but had square steel swingarm and exhaust port is on the left side.
Out of the 4 bikes their just one seat and one smashed in tank. 3 of the engines turn over and one is locked up.