1984 CR250 vs 1985 CR250

Here are the top ends of the above bikes, on the right is the 84 part #1614513 on the barrel, no # on the head on the left is an 85 Part # 1614496 on the barrel, 1614498 on the head.. The liner material is also different.
There is also major diferences to intake porting (sorry crap camera, cannot show it.

So how rare are these 84CRs, did many make it to Canada? l have a complete one, with the factory upgraded clutch side caseing,

l was going to part it out.........................but now im thinking of rebuilding it, l would be nice to have somthing that was worth more than the sum of its parts in the end though, just for a change

Thanks