Engine displacement is the volume swept by all the pistons inside the cylinders
 of an internal combustion engine in a single movement from 
top dead center (TDC) to 
bottom dead centre (BDC). It is commonly specified in cubic centimeters (
cc), (
l), or (mainly in North America) cubic inches (CID). Engine displacement does not include the total volume of the combustion chamber.
Engine displacement is determined from the bore
 and stroke
 of an engine's cylinders. The bore is the diameter
 of the circular chambers cut into the cylinder block.
 
To simplify:
 
 Try calculate this and you will get same answer.
Bore: 81 mm and Stroke: 87.3 mm
P/s: Don't forget to convert unit mm to cm.
Answer: 1798 cc