how do you get cubic centimeters?

[MagicJames]

Its Stroke x Bore right? I think I'm missing a step.... But now I'm confused because i don't know how to convert it over from metric to standard and vice versa, UGH.

[KC9LJO]

Go here: http://www.worldwidemetric.com/metcal.htm

And here: http://samson-power.com/65afx/cubic_inch_calculator.htm

[ADW3]

Pi r squared...no wait, cake are square - pie are round. :wtf:

Actually it is Pi x r squared x H, where Pi = 3.1416, r = the radius (or 1/2 the bore size) and H = the height (or stroke) of the cylinder. If you use metric units (centimeters) for r and H then you'll get cc's. Pi is constant, regardless of the units. Remember, if you have multiple cylinders you have to do it for each one and combine them for total engine displacement.

KC9LJO's links make it super easy to do, but if you want to know the math behind it...

[3wheelergod]

Take half the bore
Times it by itself
times it by pie
Times it by stroke
This gives you mm. Take the first 3 numbers and bingo!

Example....
70mm bore 64.9 mm stroke.

70 / 2 = 35
35 x 35 = 1225
1225 x 3.14159 =3848.44775
3848.44775 x 64.9 = 249764.258......

So you got 249.76cc's Simple!

[TimSr]

.7854 x bore x bore x stroke then move decimal three places to the left