The ‘CYCLONE’ TM400R

.Nicknamed the ‘CYCLONE’ the TM400R was the first Japanese production motocrosser to be mass-produced. The huge 82.5mm bore piston turned out 40 bhp at 6,500 rpm and along with the fan-finned cylinder head it had a compression ratio of 7.3 : 1. The crankshaft halves were not full circle type as fitted to most two-stroke engines and made the engine rev more; one answer was to fit aftermarket