Dr ATV piston question

[apophis13]

DrATV lists a larger piston for my S90 (or CT90), but shows no cylinder to go with it. I have checked the site and cannot find a matching new cylinder... Is this assuming a bore out?

BIG_BORE_KIT 54MM_BORE_KIT CT90_ATC90_ST90 CL/SL/S90_CM91 (90+4MM)

[Miniac]

I have an ancient jug off a CL90 out in the garage and I just miked the portion that sticks out the bottom. It's 56.95mm in diameter. Assuming your cylinder is the same that would give you about 1.5mm of wall down there in the area where the piston skirt runs after boring. It's not a lot, but it should be enough. I've bored a couple of 70 cylinders to 50mm which leaves only ~1mm, . . . it's mighty thin (about the thickness of a dime) but I've never had any problems yet.

So it sounds to me like a bore to size installation. Just make sure your machinist knows what he's doing. And be sure you don't drop it after it's bored.

-kevin