Targets for the application of the rotary valve train on the 125cc motorcycle engine

• Demonstration of the package and weight benefits


• Increase of maximum torque and reduction of fuel consumption by high compression ratio and  decrease of friction losses


• De-throttling at part load by high exhaust gas reduction (EGR)


• Perpetuation of original carburator and silencer equipment


• Reduction of engine noise emissions

Results of the rotary valve train on the 125cc motorcycle engine

• The engine dimensions of the cylinder head had been reduced significantly. Weight savings of 2,5 Kg and height savings of 80mm had been realized.


• The peak performance had been achieved in combination with a much improved torque characteristic (see figure-performance diagram)


• A high compression ratio of 14:1 without knocking phenomena had been realized


• The engine had been de-throttled essential by EGR


• During the field tests the fuel consumption had been reduced from 3,2 L/100km (original engine) to 2,8 L/100km for the rotary valve engine


• The noise emission at near sound field had been decreased for 2 dBA