I have one also... It says Honda Hobbit on the gas tank.
the registration plate behind the headlight says PA50I...1978
I just call it a PA50...(I add the "I" if somebody gets technical)
It seems odd that yours is also a 78 but says PA50II... I thought PA50II's came in later years.
If you go to buy parts... ask for parts for a 1978 PA50II.
PA50I's did 21mph... PA50II's do about 29mph... I know the cylinder and reed valve are different... and maybe the variator too.