Thread: Engine size?

I recently bought a new Zongshen off Ebay. It says 70 on the cylinder but is there any way to tell the actual cc? The intake port on the head is much larger than the stock Honda 70 motor it replaced.

Sure. Take the head off to measure the stroke (rotate the crankshaft and measure how far the piston travels. Then measure the diameter of the bore. Then divide the diameter by 2, square the result, multiply that by pi, then that result by the stroke. That will give you the displacement in cubic whatever units you were measuring (inches, mm, cm, etc.) Measuring in cm will give you cc's.

Cheers!

John

I will take a break from my quantative reasoning class and do just that . I havent seen many clone 70cc engines but I had heard that there were some cheater motors that were 125 with 70cc cylinder markings.....I think I will just ride it and not worry about it.....

That's what I would do.

;{>

John