Thank you very much for such a detail response, very much appreciated.
You have the model correct also, its an evolution 2000. Yes the sprocket is welded to the longer shaft. Our local dealer says all these parts are obsolete & unobtainable now that's what brings me to attempting this. Don't mind a bit of tinkering with such things anyway.
Both your suggestions are spot on. I was just concerned that either of these methods will move the sprocket inwards on the axle by either the thickness of the new backing plate for the differential or the thickness of the old sprocket if machined down & left. This will cause a misalignment with the top sprocket. Although I should look a this in more detail it may be simplest to preform your second suggestion on the rear sprocket, then machine equal to the old sprocket thickness from the inside of the top sprocket & make a spacer to go the other side.
I will check for clearances ect today.
Thank you very much for your time
