Engine Type: One-Cylinder
Displacement: 139cc/8.5ci
Bore x Stroke: 62 x 46mm/2.44 x 1.81in
Full Throttle RPM Range: 4000-5000
Horsepower Rating at Propshaft: 4h..
Yamaha’s
smallest Portables, the F6, F4 and F2.5, weigh in at as little as 37
pounds, with streamlined overhead-valve, one-cylinder designs. Their
light weights, combined wit..