Moto Guzzi V 7700 Episode: 15
No Harley, that's a Moto Guzzi V7 700.
Harley-Davidson EL Episode: 16
Ep. 18 No Harley, thats an Indian. Theyve tried to veil the head-shaped light and the horn, but its still unmistakable. Why is this now a 1946 Knucklehead when I just stated it isn't a Harley? I guess it's because someone disagreed with you..? When you Google 1946 Harley-Davidson Knucklehead you get a pretty close match, whereas I fail to see the apparent obvious Indian connection. Looks like the same bike from the Fourth series: /vehicle_974720-Harley-Davidson-EL.html
'tis a 36-48 Knuckle, 61" EL or 74" FL. I probably dated the other one as a 46 based on this Classic era Indians were all sidevalve.
Ducati 750 SS Episode: 18
Round case engine, 1974 Ducati 750 SS.
Ducati 916 Episode: 5
@the sad biker, anything? Ducati, a bit generic but maybe 916? Looks a lot like a Honda NR750 to me, TBH.
No cooling vents in the seat unit.