stock vs. pro lite

[Eddiesanders250]

Real quick question... Why does the stock piston have a square hole in the back of it and the wiseco pro lites dont? Im only asking because a machinist I took it to said that piston wouldnt work...

[C-LEIGH RACING]

You sure you have the right part number piston kit.
The 87/89 Wiseco R pistons have a window cut in them.
The difference of a window being in a piston or not shouldnt be a reason for it not working, might be the wrong OD size piston ???.

Those windows in the pistons were a results of Honda seeing longer wrist pin & top end bearing life from the gas & oil flow that went through them. It also cools the underside of the piston dome as well.
Neil