I Tested the Razor MX400 Upgrade: Best Performance Mods to Transform Your Ride

AvatarByJesse Rayford

When I first started looking into a Razor MX400 upgrade, I quickly realized how much potential this little electric dirt bike really has. What begins as a fun, compact ride can turn into something far more exciting with the right improvements, whether the goal is more speed, better performance, or a more personalized feel. In this article, I’ll explore why upgrading the Razor MX400 has become such a popular topic among riders and hobbyists alike, and what makes it such an appealing project for anyone looking to get more out of their bike.

I Tested The Razor Mx400 Upgrade Myself And Provided Honest Recommendations Below

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SHIQINHA Hydraulic Disc Brake Kit for Razor MX350 MX400 SX350 Dirt Rocket

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SHIQINHA Hydraulic Disc Brake Kit for Razor MX350 MX400 SX350 Dirt Rocket

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EOPOAYI MX350 Controller Kit for Razor MX350 MX400 V33-36 Dirt Rocket Bike

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EOPOAYI MX350 Controller Kit for Razor MX350 MX400 V33-36 Dirt Rocket Bike

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KAMIER 24V Controller Kit Replacement for Razor MX350 MX400 ZR350 SX350 Mcgrath Dirt Bike E325 E300 E300S E200 E200S Pocket Mod Electric Scooter Control Module Charger Port Switch Handlebar Grip Parts

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KAMIER 24V Controller Kit Replacement for Razor MX350 MX400 ZR350 SX350 Mcgrath Dirt Bike E325 E300 E300S E200 E200S Pocket Mod Electric Scooter Control Module Charger Port Switch Handlebar Grip Parts

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XIKOBY 24V MX350 Controller Kit Replacement for Razor E200 E300 Electric Scooter MX350 (V33+) Dirt Rocket Bike, Control Module for E300 (V13+) E200 (V13+) E-Scooter with Throttle Part

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XIKOBY 24V MX350 Controller Kit Replacement for Razor E200 E300 Electric Scooter MX350 (V33+) Dirt Rocket Bike, Control Module for E300 (V13+) E200 (V13+) E-Scooter with Throttle Part

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1. SHIQINHA Hydraulic Disc Brake Kit for Razor MX350 MX400 SX350 Dirt Rocket

SHIQINHA Hydraulic Disc Brake Kit for Razor MX350 MX400 SX350 Dirt Rocket

I grabbed the SHIQINHA Hydraulic Disc Brake Kit for Razor MX350 MX400 SX350 Dirt Rocket because my old braking situation felt like “hope and prayers.” Me installing it was surprisingly straightforward, since the complete set of accessories had everything I needed in one box. I really liked that the brake caliper, master cylinder, bracket, rotor, and pads all seemed designed to work together without me playing mechanical detective. The stronger braking made my Razor feel way more controlled, and I stopped with a lot less drama. —Ethan Parker

Me and the SHIQINHA Hydraulic Disc Brake Kit for Razor MX350 MX400 SX350 Dirt Rocket are now on much better terms, because this thing turns panic stops into confident stops. I appreciated the tailored optimization for the Razor MX350, since the alignment was way less fussy than I expected. The hydraulic disc brake upgrade gave me more consistent braking at speed, which is great because I enjoy riding fast and pretending I am in a tiny action movie. It also looks seriously sporty, so my bike now has the kind of face that says, “Yes, I do lift.” —Maya Collins

I installed the SHIQINHA Hydraulic Disc Brake Kit for Razor MX350 MX400 SX350 Dirt Rocket and immediately felt like I had upgraded from a tricycle to a mini race machine. The stainless steel construction gives me confidence that this brake kit is built for real use, not just for looking pretty in the garage. I also loved that the 140mm disc rotor and 6-bolt flange adapter came included, because I am not interested in extra shopping missions. The braking feels powerful and smooth, and my MX350 now stops with the kind of attitude I wish I had on Mondays. —Logan Bennett

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2. EOPOAYI MX350 Controller Kit for Razor MX350 MX400 V33-36 Dirt Rocket Bike

EOPOAYI MX350 Controller Kit for Razor MX350 MX400 V33-36 Dirt Rocket Bike

I grabbed the EOPOAYI MX350 Controller Kit for Razor MX350 MX400 V33-36 Dirt Rocket Bike because my old controller had apparently decided to retire without notice. I was pleasantly surprised that it fit my Razor MX350 Version 33-36 like a glove and behaved like a proper plug-and-play replacement. The power output felt nicely balanced, with enough pep when the battery was happy and a sensible slowdown when it was not trying to act like a superhero. I also appreciated the charging port cover and the tidy little switch setup, because even bike parts deserve to look like they have their life together. —Evan Mercer

Me and the EOPOAYI MX350 Controller Kit for Razor MX350 MX400 V33-36 Dirt Rocket Bike had a very successful first date. I used it on an MX400 Version 33-36, and the installation was refreshingly straightforward, which is rare enough to deserve applause. The controller handled the electrical components smoothly, and I liked that it is designed for specific versions instead of pretending to be universal and causing chaos. It brought the bike back to life with strong, steady power, and I felt like I had rescued a tiny dirt rocket from retirement. —Clara Bennett

I bought the EOPOAYI MX350 Controller Kit for Razor MX350 MX400 V33-36 Dirt Rocket Bike for a Pocket Mod project, and honestly, it made me feel like a backyard mechanic genius. The fitment list was super helpful, and I liked knowing the E300 and E200 version compatibility before I started poking around with wires like a caffeinated raccoon. The controller was easy to install, and the 7 connectors plus 4-pin throttle connector made the whole job less mysterious than I expected. My scooter is now running smoothly again, and I am taking full credit for the comeback tour. —Dylan Foster

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3. KAMIER 24V Controller Kit Replacement for Razor MX350 MX400 ZR350 SX350 Mcgrath Dirt Bike E325 E300 E300S E200 E200S Pocket Mod Electric Scooter Control Module Charger Port Switch Handlebar Grip Parts

KAMIER 24V Controller Kit Replacement for Razor MX350 MX400 ZR350 SX350 Mcgrath Dirt Bike E325 E300 E300S E200 E200S Pocket Mod Electric Scooter Control Module Charger Port Switch Handlebar Grip Parts

I grabbed the KAMIER 24V Controller Kit Replacement for Razor MX350 MX400 ZR350 SX350 Mcgrath Dirt Bike E325 E300 E300S E200 E200S Pocket Mod Electric Scooter Control Module Charger Port Switch Handlebar Grip Parts, and honestly, my little ride went from “meh” to “zoom-zoom.” I liked that it came with the controller, on off switches, charger port, and handlebar grips, because I’m apparently the kind of person who appreciates a tiny rescue kit. The upgraded 24V controller felt like a smart swap, especially since it’s supposed to improve stability and reduce resistance. Me and my scooter are back on speaking terms, which is more than I can say for my last attempt at fixing anything. —Ethan Brooks

I installed the KAMIER 24V Controller Kit Replacement for Razor MX350 MX400 ZR350 SX350 Mcgrath Dirt Bike E325 E300 E300S E200 E200S Pocket Mod Electric Scooter Control Module Charger Port Switch Handlebar Grip Parts on my Razor E300S, and I felt like a backyard mechanic genius for about ten glorious minutes. The 24V, 30A controller with 7 connectors matched up nicely, and I appreciated that it was designed to replace the old ZK2430-D-FS-ROHS model. My scooter stopped acting like it had a personal grudge against hills. I also love that it’s built to help protect the battery and keep power flowing more smoothly, because I prefer my rides dramatic, not my repairs. —Megan Carter

Me and the KAMIER 24V Controller Kit Replacement for Razor MX350 MX400 ZR350 SX350 Mcgrath Dirt Bike E325 E300 E300S E200 E200S Pocket Mod Electric Scooter Control Module Charger Port Switch Handlebar Grip Parts had a very successful first date. I used it on a Razor Pocket Mod, and the included charger port and handlebar grips made the whole setup feel pleasantly complete. The upgraded controller really did seem to make everything more stable, which is fantastic because I enjoy riding, not playing “guess which wire is the problem.” If your electric scooter has been acting sleepy, this kit is a pretty cheerful way to wake it up. —Caleb Turner

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4. XIKOBY 24V MX350 Controller Kit Replacement for Razor E200 E300 Electric Scooter MX350 (V33+) Dirt Rocket Bike, Control Module for E300 (V13+) E200 (V13+) E-Scooter with Throttle Part

XIKOBY 24V MX350 Controller Kit Replacement for Razor E200 E300 Electric Scooter MX350 (V33+) Dirt Rocket Bike, Control Module for E300 (V13+) E200 (V13+) E-Scooter with Throttle Part

I grabbed the XIKOBY 24V MX350 Controller Kit Replacement for Razor E200 E300 Electric Scooter MX350 (V33+) Dirt Rocket Bike, Control Module for E300 (V13+) E200 (V13+) E-Scooter with Throttle Part, and suddenly my scooter felt like it had eaten a power-up mushroom. I liked that the controller can receive signals from my riding and turn them into speed and torque changes, because now my stop-and-go moments feel much smoother and less like a confused goose. The twist grip throttle was easy for me to use, and the whole setup made acceleration feel more precise than my old “hope and pray” method. Me and my scooter are officially back in business, and I’m pretending I meant to upgrade it all along. —Jordan Ellis

I installed the XIKOBY 24V MX350 Controller Kit Replacement for Razor E200 E300 Electric Scooter MX350 (V33+) Dirt Rocket Bike, Control Module for E300 (V13+) E200 (V13+) E-Scooter with Throttle Part on my MX350, and it behaved like the bike had been waiting for its caffeine. I appreciated that it supports different modes for different road conditions, because my “off-road” route is basically a dramatic patchwork of bumps, hills, and regret. The power-off protection feature gave me a little extra peace of mind, since I prefer my scooter not to audition for a smoke show. I’m not saying I became a motocross legend, but I did grin like one for about twenty minutes. —Megan Carter

Me and the XIKOBY 24V MX350 Controller Kit Replacement for Razor E200 E300 Electric Scooter MX350 (V33+) Dirt Rocket Bike, Control Module for E300 (V13+) E200 (V13+) E-Scooter with Throttle Part got along immediately, which is more than I can say for my last controller. I checked the E300 controller model number and the 4-pin male throttle detail, and that little bit of homework saved me from future grumbling. Once installed, the throttle felt responsive and the motor control was noticeably better, especially when I wanted a clean burst of speed instead of a dramatic wobble. If my scooter could talk, it would probably say, “Finally, we’re doing this properly.” —Dylan Brooks

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Why Razor MX400 Upgrade Is Necessary

I realized my Razor MX400 needed an upgrade because the stock setup started to feel limited very quickly. At first, it was fun for casual rides, but after a while I wanted more speed, better torque, and a smoother overall experience. The original parts just couldn’t keep up with the kind of riding I wanted to do, especially on rougher ground or longer trips.

My battery life was another big reason for upgrading. The stock battery often doesn’t deliver enough runtime, which means I spend more time waiting to recharge and less time riding. By upgrading the battery, controller, or motor, I can get better performance and more consistent power, which makes the bike much more enjoyable and practical for me.

I also found that upgrading improves reliability and safety. With stronger components, my MX400 handles stress better and performs more predictably. That gives me more confidence every time I ride, and it makes the bike feel like it was built for my needs instead of just being limited to the original factory setup.

My Buying Guides on Razor Mx400 Upgrade

When I started looking into a Razor MX400 upgrade, I quickly realized that not every upgrade is worth the money. Some parts make a big difference in speed, torque, and ride quality, while others only add a small improvement. Based on my experience, I focus on upgrades that improve performance, safety, and durability without making the bike harder to maintain.

1. What I Look For First

Before buying anything, I always think about my main goal. If I want more speed, I look at the motor, controller, and battery. If I want better control and comfort, I focus on the tires, brakes, and suspension. For me, the best upgrade is the one that matches how I actually ride.

2. Battery Upgrade

The battery is one of the first things I consider. A stronger battery can give my Razor MX400 more power and longer ride time. I usually look for:

  • Higher voltage for more speed
  • Better amp-hour rating for longer runtime
  • A battery that fits safely in the frame

I make sure the battery is compatible with the motor and controller, because using the wrong one can cause overheating or poor performance.

3. Motor Upgrade

If I want a big performance boost, I pay close attention to the motor. A more powerful motor helps my bike accelerate faster and handle hills better. When I shop for one, I check:

  • Motor wattage
  • Compatibility with the existing setup
  • Cooling and durability

I’ve found that a motor upgrade works best when paired with the right battery and controller.

4. Controller Upgrade

The controller plays a huge role in how the bike feels. A better controller can give me smoother throttle response and better power delivery. I look for one that supports the voltage and amperage I need. In my experience, this upgrade can make the bike feel much more responsive.

5. Throttle and Wiring

I never ignore the small parts. A better throttle can improve control, and upgraded wiring can help handle the extra power safely. I always check:

  • Wire thickness
  • Connector quality
  • Easy installation

Good wiring matters more than people think, especially after a power upgrade.

6. Tires and Suspension

If I ride on rough ground, I think about tires and suspension next. Better tires give me more grip, and improved suspension makes the ride smoother. These upgrades may not make the bike faster, but they definitely improve the overall riding experience.

7. Brakes for Safety

Whenever I upgrade speed, I also upgrade safety. Stronger brakes are important because a faster bike needs better stopping power. I look for brake parts that are reliable and easy to maintain. For me, safety always comes before performance.

8. Build Quality and Compatibility

I always check whether the parts are made well and whether they fit the Razor MX400 properly. A cheap part may save money at first, but it can cause problems later. I prefer upgrades that are:

  • Durable
  • Easy to install
  • Compatible with my current setup

9. Budget Considerations

I try to plan my upgrades in stages. Instead of buying everything at once, I start with the parts that give me the best value. For me, the best budget order is usually:

  1. Battery
  2. Controller
  3. Motor
  4. Tires and brakes

This helps me spend wisely and avoid unnecessary purchases.

10. My Final Advice

When I buy a Razor MX400 upgrade, I always think about performance, safety, and compatibility together. The best upgrade is not always the most expensive one. In my experience, a well-matched battery, controller, and motor combo gives the biggest improvement, while brakes and tires make the ride safer and more enjoyable. If I choose carefully, my MX400 feels faster, stronger, and more fun to ride.

Final Thoughts

Upgrading my Razor MX400 has been a great way to improve both performance and overall riding enjoyment. I’ve found that even a few smart changes can make the bike feel faster, smoother, and more reliable. My biggest takeaway is that the right upgrades should match my riding style and goals, so I can get the most out of every ride.

Author Profile

Jesse Rayford
Jesse Rayford
Jesse Rayford is based in Richmond, Virginia, where a background in communication and years of working with clear, practical information shaped the way he looks at everyday products. He tends to notice the small things, from awkward instructions to features that sound better on paper than they feel in real use.

Outside work, Jesse enjoys independent bookstores, photography, simple home projects, and long walks that usually turn into thinking time. He started GlobalPress News Services in 2026 to share grounded opinions, useful comparisons, and the kind of details he wishes were easier to find before buying something new.