If you want to be precise, measure the inside diameter of the fork tube after you remove the cap. An estimate of this, which I made from a picture of the fork cap in the service manual, is 38 mm, which is probably close enough. That's the value I'll use in the following calculation.
Convert mm to centimeters by moving the decimal place to the left one digit. For example, 38 mm = 3.8 cm.
Cross-sectional area of the inside of the fork is 3.8^2 * 3.14 / 4. That's 11.33 square centimeters.
Conveniently, you plan to remove 10 mm, or 1 cm. A ml is a cubic centimeter. So the volume is just 11.33 * 1, or 11.33 ml. [See note below]
If you measure the inside diameter of the fork tube, substitute that value for 38 mm (3.8 cm) in the calculation above.
Note: The volume of the rod that extends up from the cartridge probably takes up somewhere between 0.5 and 1.0 ml, so I'd reduce the volume calculated above by about 0.75 ml.
Blue 2007 DL650
Last edited by Sprocket; 05-23-2013 at 11:34 PM.
Reason: Added note to account for volume of rod.