Calibration can be attained once in Motor Test Mode by depressing the START key. (Access Motor Test Mode: Hold down the DISPLAY/SCROLL key while turning the power switch "ON." You will then see the test appear on the display, release the DISPLAY/SCROLL key.)
The display will read CAL and the auto-calibration process then starts. It will remain at its minimum speed for approximately 20 seconds and then will climb to half of the maximum speed and then will climb all the way to its maximum speed where it will remain for about 5-10 seconds. Please Note: The MPH will never be displayed in this mode.
Once calibration is complete the display will return to the reading test