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piston sizes
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Posted by: Eddiesanders250

how come i cant get a 68.5mm piston (87-89) style. I can only find the 86 style. Is there a power difference if you get the 86 style piston and use a spacer plate?

Posted by: punker69q

More size of pistons are avalaible in the 86 model. A cylinder spacer increase the volume of air-gas mixture avalaible in the upper part of the crankcase, giving a smoother power delivery (if I remember right), but the difference is not that big. You also have to get longer base cylinder stud.

Posted by: Eddiesanders250

i really dont want an 86 style piston because in the end it will cost more. but its a 265cc thats a common bore why no piston? how much over is a 265?

Posted by: methyman

http://209.63.57.248/techies/2004wisecopower.htm

Posted by: Eddiesanders250

the biggest size that has is a 68.25mm. I need a 68.5mm piston. This is starting to make me mad ive been looking all day. do they even make a 68.5mm piston 87-89 style?? What size is .080 over?

Posted by: beerock

the 86 cylinder sleeve was thicker and boreable to .130 over stock. the 87-89 only go to .080 over

Posted by: Eddiesanders250

well then i must have an 86 head lol.

.080 over is like a 261cc

Posted by: beerock

wait my last post isnt completely correct. im not sure if the sleeve is thicker or not. Lets just say they made more over bores for the 86 year piston then the 87-89

Posted by: methyman

Hey Beerock the sleeves are the same thickness on 86-89 cylinders. The biggest piston is 69.5mm which is a p14 .140 over bore for 86 style piston. Hey Eddiesanders250 your going to have to go to a 86 style piston with a spacer plate if you want to keep on using that cylinder.