Kunray72V 5000W Electric Brushless DC Motor Kit Temperature Sensing Motor Electric Go Kart Motor 6900RPM High Speed Motor 100A 24 Mosfet Controller for Razor Dirt Bike, Electric Motorcycles(72V5000W)

Unfortunately it looks like metal in sprockets had defect and it broke a half within first 5 minutes while bike was on the stand (not even on the road). I guess this is not something quality control can really catch. I will update review after learn how good customer service is and how fast replacement part will arrive.Update.I am changing my rating from one star to three because seller’s customer service so far is very responsive. After exchanging couple pictures they told me that replacement sprockets is on the way to me. No tracking number yet, but so far I have no reasons not to trust them.I will update my review when replacement sprockets will arrive and I will be able to test my upgraded Razor 550.Update. Kunray support is pretty good. It took probably 3 weeks, but I received two replacement sprockets and two nuts. I fixed motor and so far everything works perfectly. Updating to 5 starts since issue is not really theirs and they did their best to fix it.By the way, Razor 550 with this motor was able to do at least 40 miles per hour. It probably can go faster, but it was pretty scary at this speed on this bike. One suggestion - during upgrade you need to remove original chain tensioner because new chain is larger and at the spot which has lock it may cause ssafety issues. I didn't yet removed tensioner, but planning to do it during this weekend.

I bought this kit to upgrade my son's electric dirt bike, an SSR SRZ800. I have learned several valuable lessons from this purchase. 1) the controller is huge for a 45 amp unit, it is absolutely monsterous and was going to be really challenging to fit my application. 2) the controller is soft-start, which doesn't work for a fun dirt bike. 3) the controller is not programmable in any way. 4) The motor is horrible quality, unbalanced, and doesn't go to max rpm.This kit would earn a much better rating from me if there was an ability to program the controller and adjust parameters like direction, soft-start, peak amps, and speeds. So essentially the controller isn't a great value.Now the motor: The motor vibrated a lot and wouldn't run correctly. I tried a better Kelly Controller and it would run up, shut off, and run up again with a hall sensor error. The motor was trying to vibrate off my bench. I took it apart and it was horribly unbalanced. All of these MY1020 motors are made to a price point, but the one I got was garbage.You are much better off sourcing a motor directly and then buying a Kelly or other programmable controller and the throttle separately, it will be cheaper and better.

it does work on the razor mx-650 idk about the other one but ima asume so and just an fyi you will need to cut off some metal and very diy

I was wonder how do I charge my battery's through the controller, because there is no plug on the controller for a charger plug

Have not used yet . Instructions has phase connector and junction box. Instructional Video also has junction box (5) also. Nothing was included so I had to order from elsewhere cost me another 10 bucks.Update: for those of u whole need to reverse the motor rotation its not badFrom the esc hall connector : Splice and connect blue to yellow and yellow to blue. These are 18 gauge thin wires. Picture includedFrom the motor big azz cables yellow to yellow, blue to greenFinal Update:The phase wires were REALLY hot but this was my own fault as I connected with nut and bolkt. make sure to have a very good connection or you will have resistance =HEAT. At the end I spliced them together with a wire nut which removed the issue. I was worried that the phase wires from the motor were much larger gauge but turned out to be User Error .Motor: I hooked this up on a monster motoE1000 with a 48v 20 AH LifeP04 Battery ( This thing absolutely rips! Im 6ft 235 and I top out around 28 MPH on grass. I rode this next to a Juiced Bike with MPH gauge against my son (125 lb) and we were neck and neck.So far so good, no heat issues, battery is till running strong, seems solid so far.enjoy!

it is a very powerful motor. I will give it that, but the motor came with no mounting holes that were compatible with razor the thread for the front sprocket stripped completely when I took the bolt off.

Want a crazy power house for the second stage of your bike? This is it. Loads of torque to carry that front end in the air and plenty of speed to keep you going. If your coming from an my1020 motor I’d suggest you have some handle bar grips you can keep a hold of lol.

ive got 3 of these motor all of them broke within the first weak by the hall sensors being fried i ran the rated power do not buy