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Modifying a kids go kart

Hi I have a kids metal frame electric go kart don't know who makes it can't find any info on it but it's a fully metal frame kart with manual band brake system a 36v DC motor runs on a single 12v battery, sprocket and chain drive system, it has forward and reverse. Here's what I want to do, I would like to upgrade the speed and torque a lot. I would like to switch it over to 24v minimum or even 36v if I can find a place for all 3 batteries. I would like it to have forward and reverse still and a "dad" switch when I drive it to get full speed and limit it when the kids drive it and also wire in a remote kill switch in case it gets out of hand with them. I will switch the tires out to full rubber ones and I want this thing to smoke the tires if I want and good top speed somewhere around 20-30mph and when the kids drive it to limit them to around 7-8mph. What would I be looking at for parts here? I want the foot pedal throttle still and know I will have to change out the speed controller cause it won't hold up but I think the motor should be enough power but can check the exact specs and drive sprocket gearing. I would also like 36 led headlights which won't be a problem and 36v led taillights. Thanks in advance
A 36 Volt 1000 Watt motor would be good for a top speed of 25 mph which is right in the middle of your desired top speed range. The largest motors that we have available in 24 Volts are 750 Watts which would be good for a top speed of 20 mph and would have slower acceleration than a 36 Volt 1000 Watt motor. I feel that you would be better off using a 36 Volt 1000 Watt motor since power and speed are primarily what you are looking for.

We have a reversing switch that can be used to reverse motors of this size, and we also can make an adjustable speed limiter that goes between the accelerator pedal and controller to limit the top speed at the flick of a switch (could even be a key switch so you could lock it on slow when you are not driving it).

We do not carry any remote control switches at this point in time however they are available all over the internet so one should be easy to find that could be wired into the power switch circuit to remotely disable the kart when needed.

A 750 or 1000 Watt motor will most likely not have enough power to break traction and smoke the tires unless the kart has front brakes that a line lock can be installed onto so the front brakes alone can be applied.

We have a DC-DC Voltage converter that will drop 24 or 36 Volts down to 12 Volts so common 12 Volt LED headlights and taillights can be used.

The proper gear ratio to obtain the desired top speed is usually the most important part of the build. I can help with finding the right gear ratio and which size sprockets to use if you could let me know the diameter of the drive wheels and how many teeth are on the existing axle or wheel sprocket. Or you could figure this out yourself by using our top speed and gear ratio calculator at this link:

We could make a kit for your project with all of the parts and features that you want and the kit will be pre-wired and ready to plug together right out of the box. Or the parts could be purchased individually from our website.

Please let us know if you have any questions.
Well I want this thing as fast as possible when I ride it. I want to be able to smoke the tires on this kart and have good top speed I would be happy around the 25-30mph for now. I like the idea of the key switch for the kid mode to limit the speed. I would like a 36v DC high wattage motor that is capable of what I am looking for. I can find 36v golf cart led lighting so not a problem. I would also need high discharge deep cycle batteries and a controller to handle alot of amps that I need. I would need everything including the controller motor batteries wiring kit reversing switch key switch throttle pedal and a wiring diagram for it all including the key switch. I guess if I had the key switch I wouldn't need the remote kill switch. I can just wire the taillights and headlights to a switch. I would also like rubber tires for it do you sell them as well? I would like a parts list and price for complete. Also how would I charge the 3 12v batteries when they are wired in series? I want high amp hour batteries for longer run times especially with the high amp motor. Thanks

In order to smoke the tires without the front brakes locked up and have a 25-30 mph top speed the go kart will need to have a larger motor than the ones that we sell. Our motors go up to 1000 Watts which is just over 1 horsepower. Considering that a 4000 pound car needs at least 250 horsepower to even start to smoke the tires without using the brakes, I estimate that a go kart with one person on board would weigh around 300 pounds and need 15 to 20 horsepower to smoke the tires without using the brakes.

Etek makes a 10 horsepower 48 Volt electric motor that is fairly lightweight and two of these motors could be installed on the kart. Motors this powerful would need to have a golf cart or electric car controller to run them with. Motors and controller this large are out of the realm of the parts that we sell so I am not able to make any recommendations or kits for these type of parts. There are other online part sites that specialize in selling golf cart and homemade electric car parts which would have the parts needed for your build.

To charge three 12 Volt batteries wired in series a 36 Volt charger would be needed. The size batteries and charger that you will need for this project are also out of our realm however a golf cart or electric car parts store would have them available.

Making a go kart that can smoke the tires will most likely take a couple thousand dollars of parts. If you decide to make a less powerful kart that can go 25 mph but not smoke the tires then we can put together a kit in the four to six hundred dollar range depending on the size of batteries that you want to use.

Please let us know if you have any questions.

I have been reading different forums over the last few months and I see so many options that its confusing me.  I have a stock Razor go-kart with a make date of 2011.06.21.  It doesn't really work anymore so I have no problem scraping the existing setup.  I would like to upgrade it to make it faster and have the drive time extended.  My son is 75 pounds and growing.  Can someone recommend a complete upgraded setup.  I am pretty handy if I have to make modifications.  Thank you.

Hi Vinny, Razor makes a few different go kart models such as the Dune Buggy, Ground Force, and Ground Force Drifter. Photos of these go karts are available here. Do you know which model go kart it is?
It is the ground force go kart. Not the drifter.

To make the kart go faster it could be overvolted to 36 Volts so that the motor spins at a higher RPM and has more power. A 24 Volt 250 Watt motor running on 36 Volts will become a 500 Watt motor and its RPM will increase by 50% for a 50% faster top speed. The Razor Ground Force goes 12 MPH in stock form so it should go 18 MPH when running on 36 Volts. Here is a video of a Ground Force go kart running on 36 Volts.

The only downside to overvolting is that it makes the motor run hotter than normal which could cause it to burn out if it overheats. To help with this the Ground Force's original 24 Volt 250 Watt motor could be replaced with a 24 Volt 350 Watt or 24 Volt 500 Watt motor.

To upgrade from 24 Volts to 36 Volts the following parts would need to be replaced:

  • Battery Pack
  • Battery Pack Wiring Harness
  • Battery Charger

The original throttle, charger port, controller, and motor could be reused.

If the go kart does not have its original controller and motor, or if it does and they are burned out, then I would replace these parts with a 36 Volt controller and a 24 Volt 350 or 500 Watt motor.

I can make a parts list, or a kit out of the parts that you need. What are your thoughts on which parts you would like to replace?
I would really appreciate a parts list. I am.not opposed to changing out my motor which I believe still works fine. I believe its just my batteries that won't take a charge. I am looking for the upgrade that will make it faster and ride longer. If I could use existing parts that's great but not necessary if I can increase the performance. Thank you.

The original Razor Ground Force motor runs at 250 Watts with 24 Volts and the original battery pack is 24 Volts 8 Amp hour. So if it the motor is overvolted to run at 500 Watts then a 36 Volt 12 Amp hour battery pack would provide around the same run time as the original 24 Volt 8 Amp hour battery pack did. So for a longer ride time running at 36 Volts a 36 Volt 15Ah or 22Ah battery pack would be needed. A 36 Volt 15 Amp hour battery pack would provide around a 20% longer run time, and a 22Ah battery pack would provide around an 80% longer run time.

The dimensions of 15 Amp hour batteries are 6" long x 3-7/8" wide x 3-3/4" high, and the dimensions of of 22 Amp hour batteries are 7-1/8" long x 3" wide x 6-5/8" high. Three quantity of either of these battery sizes are needed to create a 36 Volt battery pack. I do not have a Razor Ground Force go kart to mock up a 36 Volt battery pack on so you will need to determine which size batteries to use.

If you want to use a larger 24 Volt motor to overvolt to 36 Volts, our 24 Volt 350 Watt motor with mounting base is 4-1/4" high x 4" wide x 5-1/2" long, and our 24 Volt 500 Watt motor with mounting base is 4-3/4" high x 4-1/4" wide x 6-1/2" long. Again I don't have a Razor Ground Force go kart to mock up these motor sizes on so you will need to determine which motor to use.

I can make list of compatible parts however I am not sure exactly what direction you want to go with this project so I need to ask a few questions first.

Do you want to use the existing controller, or do you want a new 36 Volt controller?

Do you want to use the existing motor, or do you want a new 350 Watt or 500 Watt motor?

What is the Amp hour rating of the three batteries that you want to use? (I need to know this to recommend the right size battery charger for them)

I would like the 500 watt motor and the 22 Ah battery setup.  If I need to replace the controller to do this I will do that also.  Would I need to change the chain or sprocket to make this motor work with the existing setup?  Is it possible to ball park the price of what I need?  I would be purchasing everything through ESP.

Thank you,


For a faster speed top speed and more power than the Ground Force go kart originally has a 36 Volt battery pack, 36 Volt controller, and 24 Volt 500 Watt motor is the most popular choice of parts to modify the go kart.

The axle sprocket does not need to be changed however a slightly longer chain may be needed because the 500 Watt motor has a larger diameter than the original 250 Watt motor.

Here is a list of these parts and their prices:

  • 24V 500W motor MOT-24500X2500 or MOT-24500X2500B - $89.95
  • 36V 1000W controller SPD-CT660B9 - $54.95
  • Thumb Throttle with 36V Lights THR-68 - $19.95
  • 36 Volt 3 Amp battery charger CHR-36V3A3P - $44.95
  • 3 Quantity of 12V 22Ah batteries BAT-12V22A ($59.95 each) - $179.85

The Ground Force's original throttle could be used with the new 36 Volt controller however its battery level indicator lights would not work with the 36 Volt battery pack because they are calibrated for a 24 Volt battery pack. A THR-68 thumb throttle with 36 Volt battery level lights could be installed with the new controller in order to have a battery level indicator.

The original battery charger port could be reused with the new controller.

The Ground Force's original power switch could be used with the new 36 Volt controller. It would need to be rewired so it went directly to the new controller's power lock connector instead of to the wiring harness between the battery pack and controller.

With the 36 Volt 22Ah battery pack and a new throttle with 36 Volt battery level indicator lights the cost of parts is around $390.00. This does not include the wire and connectors needed to make the battery pack wiring harness. We could custom make this wiring harness for 15.00, or the wire and connectors could be purchased from us for around $5.00.

Please let us know if you have any questions.

I am going to place the order for your complete list including the custom wiring harness for $15.  How do I request that when ordering?  Should I just wait to install the motor to check on the chain size or can you recommend one?

Thank you,


I am not sure if a longer chain will be needed, and if needed how long it would need to be. I imagine that if the chain needs to be longer it would only need be a link or two longer than the original chain. The original chain might be stretched from being used so I would recommend to replace it so it does not wear out the new motor's sprocket.

I can create an item number and provide a link to purchase the custom battery wiring harness. To create the custom harness item number I just need to know how many inches of wire you need between the battery pack and controller, and how long the two jumper wires between the three batteries need to be?

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