Wonderful ideas,only need to fit off-road tyres and again to check the ground clearance to avoid the bike being trapped underneath.
The added weight and friction will require the engine to work harder, more power can be obtained by adding a twin squirrel gerbil charger. In the past i have had significant problems fording this engine boost system.
The cardan shaft was not designed to regularly transmit the drive at variable angles between 20-40 degrees. This solution results in increased wear and frequent failure. It is not by chance that professional manufacturers designed the drive on the rear axle, whether they used chain or cardan power transmission on motorcycles.
That is a genius idea , on addition to it , get some weight and put on the front wheel so that it will be effective. The front wheel has traction and energy , it only needs some weight
Nice work, but you need to check the speed in front wheel as the same at rear wheel. Put tape or any sign on the tyre s at same position , after that move a few meters and check are still the same position Keep going a new idea
