Updated 5/29/2020Talked to the manufacture who offered a reasonable solution to my issues with the 2nd kit; as such, due to customer service I'm increasing my overall rating to 4 stars.I have purchased a third motor kit and will be updating my review once it arrives and is installed.Update 5/26/2020My original purchase went so well and installed so easily that I ordered a second unit for my daughters MX500.Now I understand the challenges that some of the reviewers are experiencing.Controller:1st Order - all the wires were labeled, making the wiring very straight forward2nd Order - none of the wires were labeled and the colors of the wires were slightly different than my first orderMotor:1st Order- I was able to mount the motor will minimal modifications (cut-off the foot and sunk the screws that hit the frame)- Received mounting hardware that I didn't use but would have been handy in a different situation- Very simple modifications2nd Order- Foot was mounted incorrectly and I had to remove the entire thing just to clear the frame (much more work)- The mounting screw holes were also slightly off requiring further modification.- No mounting hardware was includedBoth kits had the same performance and I was able to make both kits work correctly.Manufacturer seems to have some quality control issues and it is the luck of the draw which version of the kit you will receive.I would still order the kit, but make sure you have some level of knowledge to make it work for your application.Original ReviewPurchased the Mophorn 1800W brushless motor kit as an upgrade for my sons MX650. The largest challenge was figuring out where to place the controller that wouldn't get in the way of the bikes operations. If you upgrade to lithium or lipo batteries this would help to eliminate the issue as the batteries would take up less space.Everything is very close to plug in play with the exception of the motor. You need to remove the motor mounting bracket which is easy as it is soft metal and you need to recess two of the screws that interfere with the frame of the bike when mounting. I simply removed the two screws on the motor (one at a time), and used a drill bit slightly larger than the screw head to create a recessed hole on the motor. It worked perfectly and there was no effect on the motor.There is limited instructions regarding wiring, but both the motor and throttle are very easy to figure out especially with the included wiring harnesses.The controller includes many additional connections that we choose not to use as they are not required. The only required connections are the those to the motor, the throttle, and a set of wires labeled door lock that must be either shorted or connected to a on/off switch.The increase in performance is very obvious and brought smiles to our faces. The throttle is a bit touchy and takes some getting used to as there is an increase in torque. I can ride the bike with my 220 lb frame and motor does not get hot.I measured bike spe
Philip C. 
