How far can you bore a 250R cylinder?

A circlip came out this weekend and the wrist pin made two nice DEEP gouges in the cylinder wall.

Thanks for the info!

 

Pro-x and Wiseco list pistons up to 68mm. If it's the '86(short rod) motor, you can go to 69mm max. You cannot use the '86 pistons on the later cranks unless you run a 5mm spacer plate---which increases crankcase volume but decreases primary crankcase compression. I prefer NOT to use spacer plates. One other thing I thought I'd add---If you HAVE to resleeve DON'T. A cost analysis will show you that a sleeved cylinder(sleeve=$100+$120 or more in labor) will cost the same or MORE than a NEW OEM CYLINDER(Service Honda $212!!!). Buy the new cylinder if you think you're OVER SPECS!

 

Go to this site. . . .

http://pub20.ezboard.com/bhondatrx250r

Look under "Tech Tips" and then under Info for the Heck of it.

 

go to www.wiseco.com and see the piston sizes because 86' can have a larger piston put in it that 87-89 (correct me if im wrong about the years).

 

Thanks for all of your information. On your advice, I took my cylinder in to be bored, and if it doesn't clean up at +.080", then I will buy a new cylinder.

 

an 86 you can go either 120 or 140 over stock and an 87-89 you can go 80 over