Bore Size?

[Eddiesanders250]

i need to replace my top end on my 87' R. NAPA has told me that i need a piston with a 67.5mm bore would that be .060 over piston or what. Thanks Also when do you have to switch to an 86' piston with a spacer plate and how big can you go with that?

[Eddiesanders250]

Anybody? I need to go riding here!!!:mad: LOL

[Aceman]

67.5mm=.060

My pro-x catalog shows 86 pistons can be taken up to .120=69mm.

Now go riding!

[xlr810]

you can get the 87-89 style pistons up to 68mm typically. There is also a Wiseco Racer's Choice piston in that style up to 68.25mm. Any bigger than that and you'll have to run a spacer plate with 86 piston on your long rod motor.