cylinder bore 265

[mdh23jr]

ok i have a scratch in my cylinder, so i know i need to get it bored and honed. i think im at .30mm over right now. i have a 86 motor. should i got with a .80mm over to get it to a 261cc i think or should i go smaller. any input with this would be great, thanks.

[IcutMetl]

.30 mm would only be .012"...do you mean .030" over? I would take the cylinder to the machine shop and have them bore it to the next acceptable size. Depending on the scratch, you may not have to take that much out, and it may be more beneficial to keep all those extra bores rather than going all the way out at once if you don't have to.

[atv fan 28]

what he said^^^.

[Honda 250r 001]

Originally posted by atv fan 28
what he said^^^.

agreee. just because you bore it out and put a 1 or 2 mm bigger piston in it doesnt mean its gonnna make more power.

[mdh23jr]

ok thanks guys, ya i will just go one overbore higher, thanks.

[IcutMetl]

No problem; just what I've noticed from my experience. I went right from .020" over to .060" over...just because, and had a port job done at the same time. I also took apart the metal head gasket to run one thin portion to bump up compression. Even though I have to mix race fuel 50/50, I feel that the porting and compression bump (mainly the porting) made a much bigger difference than that small bump in bore size.

Good luck!!

[mdh23jr]

ok thanks