JWER is right if it's a pre 04 model. If it is then here's how you use the rest of the buttons:
Display settings
[A] [R] [C] [D]
Lap switch is the headlight flasher switch
Resetting the Service warning
Press Lap and R together for 5 seconds
Switching KM/H to MPH
Press A about 5 seconds until blinking
Press B to change unit of measurement
Press A for 5 seconds to confirm choice
V max Uses trip odometer #1 (Speedo)
To reset trip odometer #1 press R for 2 seconds
To display V max and distance of trip odometer 1 press B for 2 seconds
To reset V max press R for 2 seconds
AVS (Average Speed) Uses trip odometer #2
Hold down B for 2 seconds and then press again
AVS is displayed along with distance of trip odometer #2
To reset both AVS and trip odometer #2 press R for 2 seconds
Battery voltage, Setting hours, minutes & C or F degrees
Battery = Press D once.
Hours = Press D twice then press LAP until hour is set – press D to confirm.
Minutes = Press D three times then press LAP until minutes are set – D to confirm.
C or F = Press D four time then LAP to set
Chronometer (Lap Timer)
V max, AVS, and trip odometer #2 no longer functional in this mode
Press LAP and within 0.7 seconds press D to enter chronometer mode
To start timing press LAP and release immediately
To store a lap time press LAP
To display lap times press B
To cycle through the stored laps, press LAP
To reset memory press A and LAP for 2 seconds
To leave chronometer function press LAP and D
Red Line Threshold
Press C, press C again within 3 seconds. Keep pressing C until desired value is set.