1975 is one of my top 3 Christmas’s. That was the year I got a Yamaha Moto-bike B model.
I had to wait until spring thaw to ride it and on that april day about 10 things came loose or fell off but man I loved that bike. There were only two others in town an older kid had the 74 orange A model and my neighbor friend had the 76 C model.
I snapped the head tube off mine and was super bummed when my Dad brought it back from Don Culp the welder who spray painted  the whole front triangle silver so his shitty stick weld wouldn’t rust. As far as I can recall the A & B model were the same with the exceptions of the A model had a solo seat and came in Orange and Yellow, the B was only available in yellow. The C model had a plastic fender, american BB, one piece crank, and the Aluminum KYB forks.
In a way that bike started all of this for me.
1976 C model

1974 A model

Head tube decal all three models
Hot Moto-Bike Action