Piston Question for 91 CR250

Hi Guys,

I want to replace the piston in a bike I just purchased.

The current piston is a 67.5 mm

My question is if the piston is 67.5mm, does it mean the cyl has been resleeved cause according to the Wiseco web site (Chart below)
It says that the bike has a Nikasil bore?????

Piston and cylinder are nice and clean but would rather replace now then end up having a piston skirt crack in middle of summer.

If cyl is equal (not deformed) should I just order a 67.5 piston?

Thanks,

Mike

CR250
Pro-Lite
*Nikasil Bore - Cylinder sleeving or
replating required for oversizes
1986-96
66.4x72
249
66.4 - STD
66.75- 0.35
67 - 0.60
67.25 - 0.85
67.5 - 1.10
68 - 1.60
68.25 - 2.10

Is it possible that someone could have bored a nickel coated cyl without replating it. If so would it last??? To be honest the cyl is clean but just doesn't have a nickel look. I really think some bored it. Haven't had a chance to get the cyl mesured with a dial idicator to ensure it's truly round if it is, I;m probably going to slap a new piston in and keep an eye though intake or exhaust over the summer.

Any suggestions or bewares??? hehe

Mike