[Mudflap]

Originally Posted by dirtbkr188

A case in point...
I have an engine here with the engine VIN - TZH152FMH - which, according to the chart above, has a 52mm bore and 110cc displacement. I know the stroke is 49.5mm, and when the formula is applied, here is the result.
5.2 x 5.2 x 4.95 x .7854 = 105.12cc displacement

The thing is, the cylinder has a 90cc casting on it, and when I removed the head, I found that the bore size was only 47mm, not 52mm, as the engine VIN states. Applying the formula to that number -
4.7 x 4.7 x 4.95 x .7854 = 85.87cc displacement


As I said above, they are not always what they say they are.

The CG engine in my old quad was coded as 71mm bore but I measured it as 63mm so I agree they are sometimes miscoded.