moto 4 ?
#21
Serial numbers are usually on the left, lower frame section, below the shifter and flywheel cover..... Looks rusty on the part in the left side motor picture,.... the numbers are probably still there though.
#24
look at my pics you can see the 84 alt125 i had the very first atv made was very very similar looking just 2 wheels up front, far as i know it was 83 when suzuki came out with that, there should be a number on that moto4 on the frame around the footpegs, there pretty small numbers and might not even be there anymore lol, from wear and tear, i know my warriors are barely visible.
#27
#30