Ok, my ? is........How does 1 determine the cc's of the motor? Say after it is bored to the next size from stock 250. Any thing I can get here will be fine, just trying to learn...Thanks

 

well the nest size could be anything. 310 330 or whatever. later

 

OK I think (I think) that you times the bore x stroke in millimeters then convert to square centimeters or maybe just plain centimeters.

 

Thanks that help out, easyer than I thought.

 

Actually, I belive you convert the bore (diameter) to an area (assume circular). THe area of a circle is (pi) (r)**2. Pi is approximately equal to 3.1415926. THEN multiply by the stroke to get "cubic" dimensions.

 

Good reply TPH, one more note, the "R" in the equasion is radius, so cut the diameter of the bore in two for that part of the calculation. Also remember that the bores and strokes are measured in millimeters, so you will have to convert for centimeters (divide your result by 1000).
Calculation for bore and stroke in millimeters:

((Radius squared) * PI * stroke) / 1000 = cc's

So, a standard '83 air cooled 250R with a bore of 70mm and a stroke of 64.4mm would be:

((35 squared) * 3.14 * 64.4) / 1000 = 247.7 cc's

So, the next size over usually being .010" or .25mm would change the equation to bore of 70.25mm and stroke of 64.4mm

((35.125 squared) * 3.14 * 64.4) / 1000 = 249.5 cc's

 

Nebula,

The displacement is the volume of the cylinder. Dimensions are bore x stroke. The bore is the diameter or distance across the top of the cylinder, and the stroke is the height of the cylinder. The volume of the cyclinder is pi (3.14)x radius squared x height. For example, I have a 00 Grizzly 600 (actually 595) Bore is 95 mm, stroke is 84 mm. Convert the millimeters to centimeters might make it easier to end up with cc's, cubic centimeers. Divide the mm dimensions by 10, so bore is 9.5 cm, and stroke is 8.4 cm. Don't forget that the radius is 1/2 of the diameter.

3.14 x (9.5/2)^2 x 8.4 = 595.1 cc's.

Since ATV engines are sized by cc's, the bore and stroke dimensions should be given in metric units, and will probably be in mm's.

I hope this helps.

Yammer_Hummer
2000 Grizzly 595? Doesn't sound as good does it?

 

Hey everyone,thanks for all the help. All good info and now I understand it. Thanks