Bill, I am quite sure I accounted for both cylinders: In each example I wrote "a piston fires" and "the next piston fires". That would account for both cylinders.
On a four stroke engine, the crankshaft must travel 720 degrees between power strokes (up & down twice). Your quote: "One cylinder fires each revolution (360 degrees)" is exactly correct for the Bonnie's 360 engine. And that is exactly what I was saying earlier. There are 360 degrees between the time the cylinder #1 fires and the time the cylinder #2 fires. One rotation later, the sequence starts again. If I reword it:
360 DEGREE ENGINE
Cyl #1 fires
the crank rotates 360 degrees
Cyl #2 fires
the crank rotates 360 degrees (720-360=360)
Cyl #1 fires, etc...
Our bikes have a 270 degree crank, but the crankshaft still has to travel 720 degrees, so the time between power strokes is not equal like the 360 engine:
Cyl #1 fires
the crank rotates 270 degrees
Cyl #2 fires
the crank rotates 450 degrees (720-270=450)
Cyl #1 fires, etc...
A 90 degree engine would not be the same as a 270. Cyl #1 would fire and the crankshaft would move only 90 degrees before Cyl #2 fired. Our crank is a 270 crank (measured in the direction of rotation from TDC of the #1 cylinder. Visually, they would be 90 degrees apart, but it is not the same thing.
If there is no gap (as I worded it in the first example) there would be no time for the crankshaft to rotate.
Each of the examples above are valid.
