I made this in 1988 it has opposite exhaust ports with leading to a single expansion chamber
There were two designs, the other had two separate expansion chambers and it went a lot faster.
The images below are of the two into one expansion chamber design. I expect it was a bit slower
because the pressure pulse wave became confused on leaving the ports instead of having a smooth
journey.
The main point I got from this experimental design was analogous to a kitchen sink with two plug holes about
4 inches apart. There would be a dead spot in the space between them which would impede a smooth
flow out to the drain. In the engine the pressure pulse would have been torn in two directions at once.
The negative sine pulse returning to suck up the fuel-air mix through the transfer port would be fine though.
After a lot of testing I observed that it could not make more power than a regular single port design
The spark plugs however were always very much cleaner. It awlays started easily.
Unknown to me at the time the opposite exhaust port design was not new as Rotax told me they already tried it.
The water cooling was a great success and used a thermosyphonic action with no pump. Always kept nice and cool.
The bigger carb was never quite right and someone with knowledge could get this running faster.
I have three different sets of expansion chambers I made for this.
I sent the pat pending design off to manufacturers and Suzuki were quite interested, the others like Honda
said they would have to wait until the patent was granted. Rotax and Kawasaki flatly said not interested.
If you want to buy this drop me an email.
Do you think you are smart?
There is a chess puzzle lower on this page which is rather unusual
I am sure you can solve it if you understand engines.
I found this other picture of another water cooled fs1e
https://www.fs1e.co.uk/PicPage06.html
4th June 2023 Updated text GA4 Htp gone canonical this