That 90 degrees is there whether or not I wrote it down. This from Kevin Cameron of Cycle World, the reason for the famous Harley lope at idle was that when the rear cylinder was on its intake stroke the air fuel mix turned 90 degrees left after leaving the carb, as the front cylinder began its intake the air fuel mix had to stop abruptly then change directions to the right. The cams could be arranged to make one fire like yours but that was not normal.