86 250R cylinder bore max

[seth400]

hello, i have an 86 250R and i need to know what the max bore is for an 86 cylinder. right now my cylinder is reading at .097 over, the piston was .080 over. whats the max you can go? ive herd 80 and ive also herd 120 on just the 86 cylinders. does anyone know FOR SURE what the max is before i start running into problems? i need to know asap. any help would be greatly appriciated. thanks

[Taco]

you can go .120 on any cylinder but they only make the 86 style piston up to .120:D

[stupid driver]

Originally posted by Taco
.120:D

[methyman]

Curtis Sparks has pistons up to 70 mm which is the biggest. Wiseco has up to 69.5 which is '85-86- 69.50mm PI-526P14
.140 over stock.

[deathman53]

your better off getting another cylinder, my r was 80 and once it blew I rebuilt it to 100 over, that lasted about 30 hours and then 120 over and that lasted 50 hours. i pulled off the topend and the transfer ports were starting to crack. I think there is a reason that nobody rebuilds after 80 over, I know I won't

[250rmike]

dont get a new cylinder unless your going big bore and need the newer design for extra cooling just get yours resleeved and yes the max is .120

[dad400ex]

PR racing engines in Toledo OH. can take it to .120 over