Norm, what size piston ring for what size piston?

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Wevil Kenevil

Well-Known Member
Mar 4, 2022
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Sack a tomatoes California
I have several 80's and a couple 100cc motors and they all have different sizes pistons and piston ring sizes.

Can you post a table of what size rings fit what piston as per industry standard.

I know about the equation but I read so many different ring end gaps that I am totally confused.

This may seem elementary to some but I don't quite get it yet.

I have piston sizes 46.80mm with 2 mm thick rings -46.70x 2- -50mm x1.5- -49.85x2- -49.90x1.5- and several others I can't seem to find atm.

Is there a hard rule that you can show us or is it as per motor.

And thank you sir!
 
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wrench

Well-Known Member
Aug 20, 2019
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So Cal
I know about the equation but I read so many different ring end gaps that I am totally confused.
FORMULA
Ring end gap 2 stroke

Boar size, divided by 25.4 = xxxxx then X by .005" for minimum piston ring end gap
X by .007" for maximum piston ring end gap

Example for a 52mm cyl, boar
52mm Boar, divided by 25.4 = 2.047 X .005" = .010" min piston ring end gap
X .007" = .014 max piston ring end gap
 
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