Ok bit of an update.
I think I exaggerated re up down movement, though there is def some movement maybe 1-2 mm which I'm guessing would mean the needle bearing which I think you call the main bearing is prob worn out or broken.
Measured the piston 63.8 mm
Measured Barrel 63.9 mm
That's with my vernier calipers, digital not most expensive ones but atleast let's me know nothing has ever been done before. Piston just has the front arrow on it same as Kawasaki did, 100% sure orig piston.
Barrel looks ok like I said earlier, does appear to,have some slight scratches that you can just feel at base of barrel. No real nicks or lips at all around ports that I can see.
I also smoothed out the head a little, just concerned about 2 deeper holes, should they be filled with weld or something ? Or be ok , or buy new head
Let me know what you think, cheers
http://i145.photobucket.com/albums/r231/sberton/9fe89374.jpg[/img
[IMG]http://i145.photobucket.com/albums/r231/sberton/03b96835.jpg