Aha, flat slides, just a thought, the volume of the air pump (cylinder) allowing for valve overlap and cam duration, will compress a particular amount of air for each firing stroke, jetting would pretty much be based on the relationship of air to fuel ( fancy name, stoichiometric ratio) so if a known amount of fuel needs in perfect terms about 14 parts of air, the jetting rhe bike guys use, based on their cylinder volumes, cpuldossibly be calculated out to your cylinder volume.
Maybe weld a bung fitting on the exhaust at gearbox for a wide band lamba sensor, to monitor air/fuel?
Next oddity, how do these flat slides go, say, in a situation of almost wide open throttle, you lift off gas pedal, downchange to lower gear, hit brake pedal, these action cause a fair amount of vacuum, ,, will the vacuum friction affect the flat slide mechanism?
Maybe try a decent household vacuum cleaner on the engine side of one of them, open it, start vacuum, and release the open slide, stiffer return springs??
I had a Kawasaki Z1R mk 2 many moons ago, back when Suzuki made a hairy tbing called Katana, it had the flat slides, i always wondered about how big these got for car use. Honda S600 and S800 sports cars ran them, light car small engine, but i think their carbs were not quite like the normal bike carbs. Interesting!!!
On a bike, far less compression vacuum on deceleration, the slides will close.
I have often looked at rhe lens mechanism of old SLR film type cameta's, at the iris leaves, as you twist the aperture opening ring, in place of a butterfly in a normal carb or TB, again vacuum could be an issue.
