Picture Update

We painted the kart's frame and seat to our liking.

A shot of the kart's painted frame from behind.

A somewhat blurry shot of the potentiometer throttle control.

Test Ride

Having received our wires, we were able to rig up a decent 24V system to give our kart a test ride. Normally, we plan to operate on a 36V system. The kart's top speed should be increased by 50% once we complete all of the controller electronics and wiring.



We brought the kart out to a middle school track to test it out. Since we still don't have brakes and are missing several lock collars for the rear axle, we really tried to take it easy on the kart. It was also a bit difficult to control the kart's speed with our improvised (copper pipe) throttle.

Desperate Attempt to Bring the Blog Up to Speed

As our kart has started coming together, we managed to forget all about the blog. This post should bring you up to speed on our kart's status.

We attached the motor mount to the frame. The mount sits centered over the rear live axle. On top of the motor mount rests the jack-shaft. The jack-shaft is a small length of 3/4'' axle that will allow us to increase our gear ratio. The motor output shaft, which will point towards the left from this perspective, will have a 15-toothed sprocket. The sprocket that will engage the motor output sprocket will have 20 teeth. The sprocket on the right side of the jack-shaft, which will engage the sprocket on the live axle, will have 10 teeth. The rear axle sprocket has 50 teeth. Thus, a the jack-shaft will allow us to achieve a 6.666 gear ratio (20/15 x 50/10 ), increasing the torque applied to the live axle and decreasing its maximum speed.

The above image shows the parallel alignment of the jack-shaft with the live axle.


We welded some expanded steel grille to create flooring for the front of the kart. Some small steel strips were used as reinforcement, allowing the rider to place their full body weight on the flooring. The flooring serves both aesthetic and safety purposes, preventing the rider from putting his feet on the ground while the kart is moving.

All of the battery boxes have been mounted, and the we have begun wiring the batteries in series.

We are using 2-gauge wire. We were able to crimp the eyes onto the wire using a vice grip.
The above is a relatively updated image of our kart. We have actually taken a short test ride in the kart running a 12 volt system with no controller. There were some problems with the chain, many of which we think we have fixed. More on that next time.

Lots of Progress

A few weeks ago we constructed a mount for the steering column and mounted the tie rods for the first time.  Aside from the bolts used to fasten the rods being a little shaky, the steering works great.  Below are some pictures of the steering assembly:

After we got the steering on, we attached the back axle so that we could push it around our driveway.  The 50 tooth sprocket mounted on the read axle should give us some great acceleration when we get the motor hooked up.

Motor Mount Nearing Completion

About a week ago, I started working on a motor mount but never got around to finishing it. Well, it's still not quite finished. I made huge progress on it tonight though, and thought it would be worth blogging about. It's difficult to describe the mount in words, so there are many pictures in this post.


The mount consists of a pedestal on which the bulk of the motor's mass rests and two arms that will be bolted to the motor's faceplate. It was very difficult to cut the arcs in the steel. I don't have any machining tools at home, but managed to use a table saw and grinding wheel to form the arcs.


As you can see, the arcs are far from perfect, but they cradle the motor nicely.



A thick strip of vinyl from Home Depot protects the motor's casing. It's possible that the motor might overheat when wrapped in the insulative vinyl layer. We might consider removing some of the vinyl if this becomes a problem.

Bent bolts were welded to the sides of the mount as a means to attach a strap. We are still investigating different ways to strap the motor down.

Four holes still need to be drilled in the steel arms to bolt the faceplate securely to the mount.

Front Wheels

The go kart parts that we ordered on eBay arrived over the weekend. Tonight I assembled the front wheels and attached them to the frame.

The wheels were easy to assemble. The bearings that allow the front wheel to spin freely on the spindle were slid through the wheel's center and came attached to the four bolts that hold the wheel together. I used a bicycle pump to inflate the tires to 35 psi.

Before the wheels could be attached, the brackets that allow the spindles to pivot were welded to the frame. Instead of welding each bracket directly to the existing frame, I first welded a small piece of square tubing to each bracket. This allowed for a greater weld area.

The wheels fit nicely onto the spindles and spin smoothly. I stood on the front of the kart, and the wheel assembly was able to hold my full body weight.

Seat Attachment

All of the go kart seats that are sold online seem to be at least $40 plus shipping--clearly a ripoff. So, over the last couple of days, I have been keeping an eye out for junk that I would be able to use for a go kart seat. This included looking through the local dumps and recycling centers for discarded chairs. Today I finally went to Walmart and was surprised to find a perfectly suitable chair for about $7. The mounting bracket, which I did not purchase, was sold separately for about $20. As far as I can tell, the seat is meant to be mounted to the deck of a boat (I found it in the boating section).

It made sense to mount the seat to the kart so that it is removable. This way, the seat can be placed on the kart to provide its dimensions (avoiding design conflicts), but can be taken off while welding. I screwed the seat into a piece of plywood with the screws that came with the seat. The screws go directly into the plastic.

Next, I welded three tabs onto the frame of the kart. The tabs were actually recycled from the 45 degree angles cut to make two of the battery boxes. I just drilled a holes in them and welded them on.

The plywood was bolted to the frame.

The battery fits snuggly behind the seat.

After testing out the seat, I can't say I'm entirely pleased with the its rigidity. I will probably weld a forth tab to the frame at some point and might use a less flexible piece of wood for the "bracket." In reality, it probably doesn't matter how well the wood is attached to the frame, since the strength of the entire seat mount is limited by the strength of the junction between the screws and the plastic sockets.