The standard gearbox output sprocket should probably be 19 tooth, and the rear wheel sprocket 42 tooth, the primary engine shaft sprocket 18 tooth and clutch drum 43 tooth. Your bike could have been fitted with gearing for sidecar use?
Regardless of whether your gearbox is a close or wide ratio type, the top gear ratio will always be the same, as top gear is direct drive = 1:1.
