that second bike is a CZ, made in cechzovakia (spelled wrong im sure), the cooling fins on the cylinder and the tank emblem are a give away. the clincher was his signature block were its says hes got a CZ.
heres a husqvarna (no u after the q), notice the chrome spots on the tank where your knees would hug the tank. that was a husky trade mark until the early 80's. i had one of the last husky's to use that tank design, it was a 1982 wrx (not the suby) 250. it was a woods/endouro bike. i rode that thing until the early 90's, drum brakes and all
bultaco is one work,,, my pops used to ride pursang's (sp), that was the name of bultacos motorcross line in the 70's.
there your vintage motorcross lesson for today