Which statement best describes the cylinder taper measurement question, choosing the best option?

• A. Top only
• B. Middle only
• C. Top, middle, and bottom
• D. Bottom only

Answer: (C)

Measuring cylinder taper is about how the bore diameter changes along the height of the cylinder. If the bore isn’t perfectly perpendicular to the crankcase or wears unevenly, the diameter can vary from top to bottom, creating a conical shape rather than a true cylinder.

To capture that variation accurately, you need data from multiple heights. Measuring only at the top or only at the bottom could miss how the diameter changes toward the other end, and a single middle reading might not reveal a nonuniform pattern. By taking measurements at the top, middle, and bottom, you can determine both how much taper there is and whether it’s steady or irregular, providing a reliable picture of the bore’s true geometry.

In short, assessing taper correctly requires checking the bore at all three positions along its length—the top, the middle, and the bottom.