250R Cylinder Boring (need advice)

[Kasper1974]

Hey guys, well I got back to work on the teardown of the R today. My question is this, on an "85 250R, how far can it be bored out before I need a new sleeve? I checked mine today and it is rite at 67.2 to 67.3. There is a ridge where the piston hits TDC and transitions to down stroke, can I still bore this out? And if so to what size? And what size piston will I need? Thanks in advance for your help.http://www.3wheelerworld.com/images/smilies/wondering.gif

[Alberta250r]

stock bore size is 66mm and on the wiesco site they make up to a 3.5 mm oversize piston, so you can go up to 69.5mm, you should have lots of room left, another moter or 2 left in the cylinder

[Kasper1974]

Ok, thats what I was looking for, thanks for the info.