Piston size compared to CC's

[Hogggman]

What do the diff bore size equal in cc on a stock stroke engine. Like 81mm=700cc etc. just curious I have 82mm right now just curious what it is.

[Sanford]

718.3cc

[Powder]

Take .7854 x your bore diam. sqrd x the engine stroke = cc's
.7854 * (82*82) * 68 = 718.22cc

[Hogggman]

Tried the formula and I cant get it to work

[Powder]

Tried the formula and I cant get it to work
oops forgot need to multiply by number of cylinders

2 * .7854 * (82*82) * 68 * .001 = 718.22cc

[Hogggman]

That worked thanks alot thats a handy formula to have.

[steve802cc]

Area of a circle = (pi)(r2)
Times this by the height of the cylinder and you get the displacement for one cylinder.
Times this by the number of cylinders and you have the displacement for the motor.

Steve

[steve802cc]

Example
Kaw 750 motor
80mm piston = 8cm
74mm stroke = 7.4cm

displacement= (pi)(r2)(stroke)(2 of cylinders)
=(3.14)(4cm *4cm)(7.4cm)(2)
=(3.14)(16)(7.4)(2)
=(50.24)(7.4)(2)
=(371.776)(2)
=743cms squared or 743cc

Later
Steve

[Idok]

lol...

[Mile9c1]

If you're measuring the bore and stroke in centimeters, just do:

Bore X Bore X stroke X 1.57

Very easy to remember.

[Powder]

Example
Kaw 750 motor
80mm piston = 8cm
74mm stroke = 7.4cm

displacement= (pi)(r2)(stroke)(2 of cylinders)
=(3.14)(4cm *4cm)(7.4cm)(2)
=(3.14)(16)(7.4)(2)
=(50.24)(7.4)(2)
=(371.776)(2)
=743cms squared or 743cc

Later
Steve
yeah same thing I just do the lazy math version, less expressed steps.
your way = 743.93 and mine = 743.93 :biggthumpup:
:Banane01: BUT we have to convert ours from Canadian CCs to American CCs if we use your way :Banane01: