So You Want to Hot Rod Your Super 73 – Part 3 – How to Hot Rod Your Bike

A Recap of What's What

The feds have their rules: 750 watts max and a top speed of 28 mph with pedal assist. Europe is even more chill with 250W and 15.5 mph. But let's be real, you're not here to ride a mellow beach cruiser. 

So, if you're going to push your bike to the limits, the first rule is simple: be smart and stay safe. We're talking a full-face helmet and gloves at a minimum. Armor is a good idea too. We sell that stuff, but you can get it anywhere. Your local motocross shop is a good place to start.

We sell faster motors and bigger batteries and the kit you need to install them into your Super 73. See the video at the bottom.

Here's the math:

• For every 750 watts you run through your motor, you get about one horsepower.
• A 3000-watt motor is four horses.
• A lightweight bike with 3 horsepower will hit 30-40 mph, so with 4 horsepower, you can expect to hit 50 mph.

There are other ways to juice a stock motor, but the most reliable and controllable way is upgrading. But before we talk more about that, let's take a quick look at the other methods so that you are fully educated about the options:

The Hot Rodder's Guide

Back in 2019, a guy named Richard Pearce wrote an article about "Superfast Illegal Bikes," and it's basically a history lesson on how we got here.

1. Chipping / Tuning: This is the OG method. Some old bikes had speed limiters that you could disable by just moving a magnet. Manufacturers caught on and started building the limiters into the bike's brain, making it harder to mess with. Now, you can find aftermarket electronic tuners on sites like eBay, but they'll void your warranty and could fry your bike's electronics. You've been warned.

2. Off-the-shelf Models: This is where companies like Super73 and ONYX come in. They sell bikes that are already pushing the limits, advertising insane speeds while also throwing in a disclaimer that they're for "private land use only." They're basically putting the legal responsibility on you, the rider.

3. Retro-fit Kits: This is our jam. It's the most common way to get real power. You replace the entire motor and controller. But here’s the thing: be aware that your stock bike might not be built for this kind of power. If you’re putting a fast motor on a Super73 RX, for example, you might want to look into beefing up the frame. The last thing you want is for your bike to fall apart when you're going fast.

4. Overvolting: This is the most hardcore way to hot rod your bike, and it's also the riskiest. The faster a DC motor spins, the more voltage it gets. So, more voltage equals more speed. Just remember that voltage x amps = watts. A 50-volt battery at 50 amps is a 2500-watt setup that'll get you up to 40 mph or more. But you have to be careful not to "smoke out" your parts. You can get more juice to a stock 750-watt motor with a bigger battery, but you have to make sure your controller can handle the higher voltage. Check the capacitors on your controller—they'll tell you what voltage they can take. And don't forget, your old battery meter won't be accurate anymore.

Our Kits

For our Moon Eyes build, we installed an NB 3000 watt motor and controller kit with a 72 volt battery and 80 amp controller to a new Super73 RX. This combination works together and fits the RX 190 mm dropout.

The motors and controllers we sell are proven. We ran a 3000-watt NB motor and controller kit with a 72-volt battery on a new Super73 RX, and it fit perfectly with the 190 mm dropout. These kits use Sabvoton controllers, which are known for being tough enough to handle a 72-volt battery.

Just remember to do pre-ride checks, tighten all your bolts, and check your tires. At 35 - 40 mph, a Super73 is a solid bike with good reliability and hill climbing ability. With a 3000-watt motor, you'll have that extra power to blow past anything in your way. Just be sure to practice your turns and maybe watch a few motorcycle training videos before you really push it.

At 35 - 40 mph the Super 73 bikes have good  efficiency, good reliability, good hill climbing ability, at a manageable speed.  A 3000 watt motor will easily deliver this plus have that stealthy reserve power for passing. It is definitely worth your while to practice turns and take in some motorcycle training videos before riding fast.

Dropouts and Horsepower

When you're shopping for a motor kit, you need to know the "dropout" distance. This is the space between the rear fork supports. Get a ruler and measure the distance. Our kits are built for Super73's:

• Z-1: 150 mm

• S-1: 170 mm

• S-2/R/RX: 190 mm

You want a motor that fits your bike's dropout spacing. You can use washers to fit a smaller size, but you can't fit a larger one without messing with the frame.

Also, think about your tire size. Bigger tires give you higher top speed, but smaller tires give you more torque for climbing hills. Bigger tires can also put more stress on your motor, especially when you're pushing it.

Mounting the Kit in a Metal Enclosure

How do you install the bigger battery and new controller? We sell metal enclosures for mounting the batteries and controllers for the RX and S2.  We have two sizes for the RX, designed for the larger and smaller 72 volt batteries. USA-made metal enclosure for installing battery and controller.  

Resources:

For more detailed information about overvaulting and motor kits, check out the blog on electricbike.com here. https://www.electricbike.com/modified-hub-motor/