Picked this up used. Got it running by replacing all the batteries, however, when you hit the throttle the motor runs the chain in reverse. Any idea whats wrong?

Stripped freewheel or chain off of gear.

run fault codes and look for throttle position sensor problem. cat converter problems are apparent at high RPM's under load as the cat converter blocks the exhaust pipe.

Try having the cpu reset as battery changes mess up the programs

I think you are talking about an electric motor on your bike . If the motor is New you may have a bad throttle switch . You can use an ohm meter to check the throttle switch . Connect the two leads of the ohm meter to the wires of the throttle switch ( dissconected) . As you turn the throttle the ohm reading should coraspond to how much you turn it .

You need to check the voltage at the motor connections when running. Make sure the chain is not overly tight--you should be able to move it by hand, and that it is well oiled at all times. The battery seems to be ok if it runs a companion tool. Make sure the chain is properly sharpened. Hope this helps!

Sounds to me like the battery is going out on it. Not sure how much a replacement battery is, but it is where I would start.

Loosen the chain enough that you can remove it from the sprocket. Run the opener until the sprocket turns counterclockwise and stops. With the door in the open position replace the chain. You will probably need to adjust your open and close limits per your owners manual.

sync the motor. the gear kit tells you how. get motor up and position trolley near motor, assuming you left chain/cable attached to trolley). Get motor up by running motor and then pushing button again. if motor reverse, let it run and it will stop in up position.

Try checking Throttle position sensor with an ohm meter. Remove connection, put probes on pins (hit & miss on which ones, but you'll find 2 that give you a reading that increases as throttle is opened) and read meter as you open throttle all the way open & all the way back slowly & smoothly. The reading should go smooth up & down, If it jumps, or doesn't move at all in some spots, it's probably faulty. Have you tried to get any fault codes yet?

I have the same problem. I just removed the cover and discovered a nylon gear had been worn out. I found lots of shavings inside the cover. The nylon gear is beneath the exterior chain gear. I am looking for information on how to replace it, if I can find the part. If you decide to look at yours, unplug the power and remove the sheet metal screws securing the bottom portion of the cener cover to the front and back covers. Then just remove the upper screws from the center cover. Good luck.