Hi johnAh this is very interesting as i also have two cars that have 3 cylinder two stroke engines in them of 539cc these are suzuki carry vans. I just got a spare engine and want to make improvements for power and economy. I have spoken with a motor bike mechenic that used to race bikes years ago about getting him to make 3 separate expansion chambers so i can have each cylinder optimized for differant rpm ranges to broaden the power band. These engines have a seperate oil tank and a pump that sends oil to the crank shaft and to the cylinders.
Cheers Jamie