Hi Guys, I'm rusty and haven't been on a bike in 12+ years, just picked up a very nice 97 RM250 the other day for cheap to start riding with my son, he's 5 and loves the sport!! Anyway, This bike apparently has been sleeved, no plated cylinder here. I'm doing a full rebuild on it and I'm seeing pistons for "SCEM" and pistons that don't say.... do I need a particular piston for the sleeved cylinder? While I'm at it, whats the stock bore size on a 97 RM250? I'm measuring 66.25-66.30mm just a quick check with my calipers.