F Series trail bikes

Engine: 125-350cc Weight: 110-140kg Year: 1968-1975 A range of rather sophisticated trail bikes that generally few know about. Variously named Big Horn, Sidewinder, Bushwacker and Bison. Most run disc-valve induction motors, except the later 250 F11s. Superbly engineered and aesthetically different, they are easily as viable as the equivalent Yamahas but the earliest models only ran four-speed boxes in some instances. 125,175 & 250 lived on a little later as KE models with changes making them more Tarmac-orientated.