confused on piston sizes?

[Kingdom]

I just opened a used 6-bolt motor I just bought.

And the piston says 0.5 on top.

What size is that? I have heard of .020, .030, .040 over.

Im kinda confused here.





Also, how can I calculate my displacment with the new overbore?

 

[zac83]

.... Radius beeing half the circle...

(Pi * (overboreed radius) ^2 ) * Stroke
^ very rough... i would sudjest:

added displacement = ( (Pi * (overboreed radius) ^2 ) * Stroke ) - ( (Pi * (stock radius) ^2 )* stroke )

added displacement + stock (1997 cubic centimeters for instance) is your new displacement... this takes in combustion chamber area and all of that...

 

[Polk]

.5 mm=.0197"

and to figure displacement here you go

bore x bore x stroke x number of cylinders x .7854

Polk

 

[Kingdom]

thanks alot guys.

so .0197 I would assume to be the .020 bore, correct?

So I can either stay with .020 or go .040.

are their any more overbores?