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Anyone installed a brushless hub motor on razor mx650 or mx500?

anyone tried a hub motor on the razor mx650 or mx500?

Found several the right size 14.5" but not sure the 800 watts mentioned is enough to notice a significant improvement over stock.


I don't know how many watts are required for greater performance. The brushed motor that comes on the off road scooter is 650 watts but we see 1100 watts (36volts at 30 amps) often on a watt meter and I want more power/torque than this. These brushless hub motors would be much more efficient and seem like the perfect match for the Razor MX 400, Mx 500, Mx 550 and MX 650 dirt/grass scooters if they provide enough torque. I'm surprised if no one has tried it. Hesitant to be the first and find it is not an upgrade.



complete kit with twist throttle, brake levers, disc brake, controller, etc


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We have not heard of anyone who has installed a brushless hub motor on a Razor MX500 or MX650 dirt bike before however that sounds like a great modification.

If you wind up performing this modification please keep us up to date on its progress and results.

Here's another idea. 1800 watt brushless motor, same size as the stock 650 Watt. Not sure if the 4400 rpm is too much. I believe the stock motor is around 2750 rpm. The 800 watt brushed motor is 2800 rpm and the 1000 watt 3000 rpm.

We carry the Boma brand 48 Volt 1800 Watt 4400 RPM brushless motors on this page:

The increased RPM of the 1800 Watt motor is proportionate to the increased power that it has so the size of the wheel sprocket will not need to be changed and the speed of the bike will be almost doubled. These 1800 Watt motors have sprockets for 8mm chain so the original MX500 or MX650 wheel sprocket will need to be changed over from a #25 sprocket to an 8mm sprocket. #25 chain can but should not be used with a 1800 Watt motor anyways so switching over to 8mm chain is necessary in order for the drivetrain to be reliable. We are having both 62 tooth, 63tooth , 72tooth , and 84 tooth sprockets for 8mm chain that will fit the MX500 and MX650 which are available on this page:

Both the stock motor and the 1800w motor have 12mm shafts.  I cannot tell if both have the same diameter for threads to mount sprocket to motor.  Do you know if we can simply remove the sprocket that comes on the 1800W motor and replace with stock one?  Is there somewhere to buy a #25 sprocket that will fit to allow same chain and rear sprocket?

Any idea if the motor mounts line up? I can probably make something if not.

Do you know if the 1800 watt motor data for 4400RPM is under load or no load?  In RC applications the brushless motors are listed in Kv and it is no load.  If it's under load then its fair to assume it would double the speed of the bike as I find it runs at about 2700RPM under load with my son riding at 16mph flat out in level dirt/grass.

Have you come across any performance data for this motor?  Watts, amps, volts, rpm or torque? 

thanks for your insight.  Seems few others know much.

The original MX500/MX650 sprocket will directly fit onto the 48 Volt 1800 Watt brushless motor.

The 1800 Watt motor mounts using the same bolt holes as the original motor.

The 1800 Watt motor's 4400 RPM rating is with no load on the motor. In many circumstances such riding on flat ground the motor will run at its full speed unless the bike is going uphill. The motor will spin faster when not under load or when going downhill. Electric motors have a lot of torque so during most riding conditions they will run near tor at their RPM rating.

I would expect for the 1800 Watt motor to nearly double the speed of the Razor MX500 or MX650 dirt bike compared to the original motor if the same gear ratio is used. The factory that makes the 1800 Watt brushless motor has not provided us with any data other than what is on the motor's nameplate so all I know is the Voltage, Wattage, and RPM of the motor. I will check and see if we can get any further performance data from the factory though and if we can then I will post it here.

I've ordered the 48v 1800w motor with controller, brake levers and twist throttle.  I will install #25 sprocket on it from stock motor.  May have to swap sprockets for new ones either larger or smaller to trade speed for torque if it's too fast for my son.  Supposed to have in 2 weeks.  Will let you know how it goes.  Will start with 36v and go up from there.  Thanks for the insight, much appreciated.

Most 48 Volt brushless controllers have a low Voltage cutoff at around 42 Volts and will not work with a 36 Volt battery pack. You might want to check the low Voltage cut off value of the 48 Volt controller to see if it will run on a 36 Volt battery pack.

Thanks for mentioning.  I've asked about the cut off voltage.  would be nice to be able to select the cutoff voltage like with RC controllers.  If not I'll want to order a 36v and a 48v so I can try both

I thought I should warn you about the low Voltage cut off so you can get the right parts. We are looking forward to hearing how this 1800 watt motor upgrade modification goes so please keep us updated on its progress.

ESP Support, thanks fort the info.  I have the brushless 48v 1800w motor installed and tested on 36v and today will test higher voltages.  I am pretty concerned about the current it draws with the 36v set up.  It allows a couple more mph at a couple more amps.  It almost seems like power consumption vs speed is linear.  I would expect a brushless motor to be far more efficient than the original brushed motor.  Any thoughts?  I wanted to try a smaller motor sprocket and larger rear sprocket as there may be better efficiency at higher volts but at this rate i'm afraid I'll be at 45A or so at 48v.

Info here

Figured it out.  The controller limits the current to 30 amps so regardless of voltage it will be just under 30 amps.  Next I'll test the "Double Speed" connector to see what that does.  Not sure how that will happen if current limited to 30A.  Also curious to see what a 13tooth sprocket will do on motor compared to 11.

Thanks for the update. Great to hear that you got it installed and running.

Brushless motors are supposed to be around 10% more efficient than brushed motors are. I agree with you that the maximum efficiency of a 48 Volt brushless motor might not be fully realized when running it on 36 Volts though due to the lower RPM that it would run at. Hopefully when you run it at 48 Volts there will be a significant increase in efficiency.

The "Double Speed" connector most likely cuts the speed in half. On all BLDC controllers that I have used the double speed or half speed connector cuts the speed by 50% when its wires are bridged together. Hopefully your controller is wired so the speed will double when they are connected though.

How did the 48V 1500W brushless motor fit into the MX500 frame? Was it the right size and bolted right in without modification?
It ran much better at higher voltage. I think 58v is equivalent of 4 lead acid batteries fully charged in series. I tested to 56v. It just need a 2mm spacer on the face and two 8mm spacers on the back side to fit. Volt pattern the same and same volts reused from stock motor. You have to check out the results here. What on earth is the purpose of a "half Speed" connector? I just ordered a handle bar mounted switch button from you to hook up to this double speed connector. Was wondering how it would increase speed at all without going over 30A limitation. Assumed it gave a momentary increase in current above 30A. Willreport in other thread.

The half speed connector cuts the controller power output in half when a switch is connected to it and on. This can be used to conserve battery power and get a longer ride time. Some people also use it as a training mode for younger riders. The funny thing is that many scooter manufactures call it a turbo button instead of a half speed button because if you turn it off the speed doubles.

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