How To Build an Electric GoKart

I can only go so long doing mindless coding projects at work. Sometimes I need to do something real. The kids really liked the neighbors' gas powered go-kart. Always wanting to do more than the minimum, I decided to create something uber cool. What's cooler than a trike?

I started pricing the parts for a gas powered scooter and found that it was cheaper to make it electric, even though I already have a 6.5HP gas motor new, still in the box, in the garage.

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Sketch out the idea

First of all I looked online at a few dozen trikes. There were a lot of awesome ones out there. Some came with hot chicks in bathing suits. Being married, however, I was barred from creating one of these. :s

Finally I found one that I liked and tried to base my design on its structure since my creative side is sorely lacking.

Get the tools

How does one create such sweet bends without spending a fortune? Try a Harbor Freight bender. Unfortunately I learned quickly that Harbor Freight tools are garbage. Check out the nice kinks generated.

Finally I decided on a whole new design, one that used smaller, less expensive bends. So I needed a tubing bender. I purchased the Pro-Tools MB-105 manual bender for $199. It worked beautifully. Of course compared to a Harbor Freight piece of garbage, anything would be awesome. :) Seriously though, if you're going to buy a bender, get this tool. I built my own stand for it and there is no way to get the perfect angle without their pointer assembly, but I didn't want to spend the extra money.

Get the Parts

Since I didn't lay it out on paper first I had to guess what I'd need. Luckily I've done this enough times I was almost right on. The items in red were returned. I picked up the following parts:

Company Qty Part Unit Cost Total Cost Return Reason / Notes
Pro-Tools.com 1 MB-105 Tubing bender $199.00 $199.00  
Pro-Tools.com 1 100034000 Pro Model 105 Round Tube Die 1 1/4x4.5" 120 degree $210.00 $210.00  
Harbor Freight 1 32888 Pipe Bender $79.99 $79.99 Garbage. Crimped pipes.
Harbor Freight 1 38471 Compact Bender - Bench $63.99 $63.99 Garbage. Crimped pipes.
Harbor Freight 1 42324 Pipe/tube notcher $44.99 $44.99 Garbage. WAY out of alignment. Had to use washers to get things lined up enough to make it work. Typical for HF.
Barmon Lumber 1 1 1/4" Hole Saw $9.49 $9.49 Disintegrated on first cut through pipe. They don't allow returns even if they sell garbage.
Lowe's 1 Lenox 1 1/4" Hole Saw $8.47 $8.47 Disintegrated on third cut through pipe. They exchanged it for a new one though.
Lowe's 1 89137 Rust-Oleum 20 Oz. Red Gloss Spray Paint $6.28 $6.28  
Lowe's 1 White Spray Primer $6.00 $6.00
Highway Auto Supply 1 V502HF Tractor Light 3x5Hal $20.98 $20.98
Highway Auto Supply 1 5141PT 3/8" x 10' Split Loom $3.68 $3.68
Yosemite Bicycles 1 Sunlite Series II Chain Tool $8.12 $8.12 Wrong tool for #25 chain. Less expensive to keep than return.
Amazon.com 1 #25 Chain, 10' $11.92 $11.92
Amazon.com 1 Roller Chain Connector Master Link, 4-pack #25 $3.75 $3.75
Amazon.com 2 Attwood 9065-1 Battery Box w/Strap Vented $11.77 $23.54
Everett Steel, Inc. 2 Rd Tube 1.25OD x 1.12ID .065ID .065WA x 20'0" $39.00 $78.00 Never call during the week or send a request through the web site. They're lazy assholes. Go in on Saturday. The guy working there is the only reason I go back.
Everett Steel, Inc. 1 Diamond plate aluminum panel
Everett Steel, Inc. 1 2' x 1' x 3/16" Steel plate      
  1 Junk child's 16" bicycle $0.00 $0.00 Used handlebars, handlebar neck. V1.0 used the front fork assembly.
FlagBoss.com 1 Confederate Skull Flag - 3 x 5 $11.95 $11.95 Utter and total garbage! Can see right through it, graphic barely visible.
ElectricScooterParts.com 2 WHL-350RB Rear Wheel Assembly $49.95 $99.90  
ElectricScooterParts.com 1 THR-46 Hall-Effect Twist Throttle with 24V LED Meter $24.95 $24.95  
ElectricScooterParts.com 1 LEV-30 Left Side Brake Lever With Brake Switch $15.95 $15.95  
ElectricScooterParts.com 1 GRP-40 Magura Waffle Style Handlebar Grip $1.98 $1.98  
MonsterScooterParts.com 1 Z09-1706 - 24 Volt 1000 Watt Permanent Magnet Universal Driver $46.99 $46.99  
MonsterScooterParts.com 2 C80-8751 - 24 Volt 500 Watt Electric Motor with 11 Tooth Sprocket $64.99 $129.98  
In Stock 8 Self-Tapping Sheet Metal Screws      
Pacific Power Batteries 2 Group 24 12V batteries      
Lowe's 1 10' Camper Shell Padding      

Make the Frame

The frame is the most important part of the trike. It has to support the seat, the wheels, the motors, steering, etc. I hate square corners so I bought a bender to make them all rounded.


I measured the wheel sizes for the WHL-350RB assemblies and determined the width for the wheel wells. Created curved wheel wells for them.

NOTE: these wheel wells were eventually recreated and moved to the back of the frame to keep the trike from flipping over. Had to extend one end to meet up with the back of the frame.

I figured out the minimum width for the battery and seat area and bent two pieces of steel to act as the outer edge. Lined up all the parts to verify it'd work.

Cut some wheel mounts out of square pieces of steel and cut out spots to bolt on the axles. Welded them to the wheel wells and the outer frame.

How to steer was a big question. They sell steering kits, but they're expensive. I ended up cutting the neck off of an old bicycle of my daughter's. Also cut a teardrop shaped piece of steel to attach to the frame. Welded all of that together.

Had to really clean up the bicycle neck. Removed the bearings, cleaned them up. Cleaned out all the grease from the tube, grinded off the paint, etc.

I welded together all of the major frame parts and mounted the tires to get an idea of how it'd look.

Attach the Front Wheel

Modeling a bicycle, I decided on a single stick for the front wheel. I simply used the front forks off of another bicycle laying around and welded on an extenstion to make sure the bed was flat on the trike.

In order to use the bicycle fork I had to weld on the lower bearing retainer to the extension tube. You can see that in the second photo near the clamp.

I painted the parts silver to make a cool, new looking fork assembly.

The new fork assembly easily slid into the neck and the trike began to take shape.

NOTE: Later this design had to be revamped. Replaced this single with a double fork assembly.

Attach the Motors

The rear wheels were pretty much attached, but needed to attach the motors. Created some bolt brackets for the motors so that they could sit up above the wheels. Biggest problem here was making sure he bolts didn't iterfere with the chains. Took quite a bit of work to figure out the angles and how to design the mounts, get them welded on and tested.

Cutting the chain was easy enough. Just used a nail punch and a hammer to knock the pins out, added a master link to each.

NOTE: This mounting bracket also had to be revamped when the wheel well was moved to the back of the frame. Whee.

Finish the Frame

The rest of the frame was a matter of just adding cross supports and a central support for the seat. When doing this I noticed that the wheels were too close to the front so it flipped over easily. Only way to fix it was to move the wheels as far back as possible.

Of course since it was nearly complete the kids wanted to jump on and try it out so I pushed them around the neighborhood. In doing so I realized they'd need a place to put their feet other than the flat top. I bent and welded a foot rest in the front.

Now that the frame was done I could add the plate to cover the frame. Cut a piece of diamond plate aluminum which always looks awesome.

A HUGE THANK YOU TO MILLER WELDS for helping me get my plasma cutter back up and running. It died during construction. They fixed it up good as new. Way to stand behind your products guys!

Paint It

This is when all the hard work seems worth it. Even a layer of primer on bare steel makes it look awesome.

In these views you can see the wheelie wheel mounts I put on the back. This thing takes off so fast if you don't sit forward it would flip over. :s

Wire It Up

Now that it's painted and ready to assemble, just had to wire up the motor controller, the motors, batteries, throttle and brakes. Don't have photos of those yet, will have to get some and write up that area. It took some time to do it right and hide all the mess.

Enhance It

Version 1.0 worked well, but the front fork was too easily bent. With 100 little undisciplined kids in an HOA jumping all over the trike I had to reinforce the design. Came up with this dual pronged design. Much stronger and it looked mean. Added a headlight so the kids could ride it at night.

Questions?

If you'd like to build your own I'd be happy to tell you all about my mistakes and ways to make this even cooler. Feel free to contact me and I'll get back to you.

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