the minibike I guess I had 13.5” tires and 6.75:1 sprocket ratio. 8T on front, 54T in back.
Skip to 2:15 for top speed run slightly uphill.
Black Mamba Jr Cam,
26 lb valve springs,
SS valves,
Billet Retainers and keepers,
ARC +0.020" Billet Connecting Rod,
gx390 carb,
NR zero degree adapter...