formulation for cc's

[masonryman13]

What is the format used for figuring the cc's on a 2-stroke??
started as a 250-- now bored out to a 75mm piston(stock is 70).
Thanx, just curious..........

[Kryten]

First convert your dimensions to centimeters (75mm = 7.5cm).

You are trying to find the volume of the cylinder, thus you need to know the stroke as well.

V = pi X r^2 X H, where r = 1/2 the bore (radius).

I'll use a 1986 200X for an example. Bore X Stroke - 65.0mm x 60.0mm

V = 3.14 X (6.5cm/2)^2 X 6cm = 199cc

Please correct my if that's wrong.

[masonryman13]

i'm even more confused ????

[03 ORANGE SHEE]

bore x bore x stroke x.7854 = cc ;)

[Kryten]

1. Take your bore of 75mm, convert to centimeters (7.5cm).
2. Divide that in half to get your radius and square it.
3. Multiply that number times Pi.
4. Now take that number and multiply it by your stroke (in centimeters). If you give your exact model someone here will know what the stock stroke is. You have now calculated the volume of your cylinder in CC's.

Pi or π is a mathematical constant, approximately equal to 3.14159. It represents the ratio of any circle's circumference to its diameter in Euclidean geometry, which is the same as the ratio of a circle's area to the square of its radius.

Hope that helps.

[masonryman13]

ok, the stroke is what i dont know. its a 84 honda 250r atc

[masonryman13]

ok-- got it. 64.4mm is the stroke. 75mm is the piston. from my math its @ 285cc??

[Kryten]

Yes, that sounds correct.

[masonryman13]

thanx so much for your help....

[Yamahondaman]

Also ... Cubic Inch is .061XCC's = , for instance , .061X250=15.25 Cubic Inch
it's like when them Harley guy's say .. "I HAVE A 90 Cubic Inch" thay have a 1475cc Motor....
a TRI-Zinger is 3.66 .. , i think Jason Hall's ZINGER is 4.5 Cubic Inches !!! :naughty:

[The Goat]

jesus...the guy who bought my truck not that long ago had a 191 cubic inch motor on his bike....thats twice the size of the engine on my car...