Loss of power
The motorboard gives few indications of problems to the operator, besides three LEDs and a buzzer. The most common indication of a problem is a loss of power, it also is one of the most difficult problem for a motorboard owner to diagnose.
A obvious cause of low or slow performance is simply a low-level battery charge, even if the GREEN indicator light is illuminated. The YELLOW and RED leds do not light until the batter is almost completely discharged. You will notice significant degredation in performance long before that point.
Another cause is a poorly charged battery due to a malfunctioning battery charger. The battery charger has an automatic cut off mechanism to prevent overcharging. It seems that this mechanism can be affected by temperature, and the charger may not charge it too cold or plugged in in the wrong order. For further information see Battery charger information.
Lastly Lead Acid and NiMH batteries need to be "conditioned" every ten charges. This involves completely draining and recharging the battery. LiIon batteries should NOT be conditioned.
Under perfect conditions, Lead Acid and NiMH batteries are rated at only about 500 cycles, or 12 months (2 rides x 20 workdays x 12 months ) of daily use. LiIon batteries are rated at 2000 or more cycles or about 4 years of daily use. Another sources says "500 - 1,000 charge cycles (depending on use, this could be 2 - 5 years)".
Because the 2000XR motorboard uses friction drive, where the motor rubs against the motor wheel, a common cause of poor performance could be that the sidewalls of your rear tire are dirty, or have been worn down by normal wear, notched or cracked because of rocks, or riding through water, or using too much power on a steep hill.
The sidewalls should be clean with a small amount rubbing alcohol before (or after) every use. If that does not remedy the situation, you can swap the front and rear wheels. After both wheels have been used in the drive system, then a new wheel must be purchased.
If you hear a persistent clicking noise coming from the rear wheel then check the rear wheel for notches chewed out by the drive spindles. The manual also says to check forground rubber “grit” similar to the residue you see from a used eraser, but I have not seen this. Instead use sand paper to smooth down edges and cracks that appear.
Traveling with notches or cracks in the sidewalls of the rear tire may damage one or both motors. If this type of tire damage has occurred, the wheel, bearings, and spacer should be replaced immediately.
The clicking noise may also be the result of a cracked wheel due to hard cornering with a heavier rider.
Loose motor connections
Dirty motor brushes
Motor controller faulty
One motor faulty
It is possible that loss of power is due to only one motor functioning. You can check if this is the case by placing the motorboard on a workbench, using a rubber band to hold down the throttle, and removing one bolt from the rear wheel. Turn on the motorboard, and press down the throttle, then spin the rear wheel until it moves by itself. Then remove the rear wheel bolt and let the rear wheel fall out. Then observe if both motors are still moving or only one. If only one is moving, then check its connections, clean its brushes, or replace it entirely.
Another possibility is one motor has reduced power output. This can be determined by placing the motorboard on a workbench and opening it up (follow ALL standard safety precautions!). For the 2000XR, remove the battery and the power switch. Turn the motor sled over and mount it on the base cavity upside with a few screws. Reconnect the power switch and the battery. Disconnect the black wire at the connector between the battery and the motor controller. Disconnect the black wires on the motors. Connect a wire between battery black wire of the battery and one of the motors. It should run at full speed. Do the same with the other motor. Observe that the "sound" and "feel" of both motors at full speed is the same. This test involves dangerously high voltages, be sure you know what you are doing and that you are qualified before trying this.