1990s did not have boreable liners; they had coated ones like most Japanese brands did. New Piston had a blue ink capital A or B marked on them. All YZs had coated liners from later 80's on as most all the Japs did. LA Sleeve has I believe 280 kits that are boreable with existing useless coated cylinders.
What color are the upper fork tubes? Silver, Blue, Red? Where the triple tree connects. Frame color? Black, Red, White, Yellow?
Frame numbers were on the right side of steering stem or small poss. center of stem. Seems to me right side.
11th number or letter; but it's the 11th.
Owned two of these bikes; looking to purchase another as mentioned in the forum...