Which piston ring?

1983 250WR.

Piston crown is stamped 69.68 and M11

I'm not sure what the standard bore is or which ring to order - my ring is out of spec (over .8mm) but the piston skirt is within spec (0.3mm)

I assume this is a stock piston but not sure...any help greatly appreciated (funny how replacing fork seals turns into "may as well clean the motor" to "may as well remove the cylinder and check the piston..."

Your piston is the first over size.

Marty

Thanks Marty.

If I decide to replace the piston and rebore, what size piston should I order?

I’m thinking the skirt gap is already close to being out of spec so maybe just go up a size?

you have to get the cylinder to a machinist who is going to do the job for you. he will bore until it cleans up, then measure. i give them a list of available sizes, so they will know what the sizes are. you have no idea how much needs bored until you do it. next size up may not be enough, but you also dont want to bore more than what is needed. i then order the correct size and they finish it to match the piston.

Yeah I was hoping I could identify a piston, have it shipped to me, then take it and the cylinder to the machinist to save some time. I don't know any local machinists where I am.