I love the project

Thanks in advance.

I’d like to see the fuel tank with a curved front end and it does look like the centre pipe will get hit by the front wheel on full bump. That could be solved with a Hossack front end and give even better handling.

On the subject of strokers, the expansion chambers are tuned to suit the revs where the engine makes max power. Gasses exit the exhaust port with a bang as the port open suddenly (unlike poppet valves that ramp open). The shockwave expands down the diverging cone creating a suction behind it that pulls mixture into the cylinder and down the pipe. the shockwave bounces back of the far end of the chamber and pushes the mixture back into the cylinder just before the port shuts. Due to gas inertia the cylinder is filled from both sides. During the closed period gasses emerge from the stinger pipe.

The pipe’s overall length is governed by engine speed. Often there is not enough length if they are run out the back of the cylinder. High revs allow a shorter pipe but strokers rarely work above 10,000 rpm.

All this is about the speed of sound in a hot gas so the temperature and pressure all affect how it works. Add in the porting etc etc and its complex stuff to get working right. All thanks to Walter Kaaden, the guy who designed MZ engines in Eastern Germany after WW2. He never patented his invention and died penniless.