You may have a backyard sit-on lawn mower that became too much work, as the deck rotted and the mower stopped working. All the ride-on mower is good at now is for towing wagons, and it’s not very good at that. One thing that depends on the lawn mower is the engine, tires, and a few other essential things for a fantastic go kart.
Unfortunately, the ride-on mower requires some education to drive, a clutch is required here and an adjustment there to get the unit to work. Therefore, using the lawnmower as a makeshift kart is not realistic or safe.
You had some other intentions for this rusty helmet that you haven’t figured out yet. You still haven’t figured out how it is possible to transform lawnmower parts into a go-kart that is sure to put a smile on everyone’s face.
The transformation requires the following:
- go kart map
- vertical motor drive
- Pipe for the framework
- Wood, fabric and foam for the seat.
- Rear axle and drive sprocket
- Rear axle bearings
- Clutch
- string
- braking system
Tools needed:
- welder
- Hacksaw Saws-all with metal cutting blades
- Standard wrench set (includes allen wrenches, hammer, sockets, locking pliers, and screwdrivers)
- gold drill and drill
The rest of the mower elements can be used for the kart. The front tires, the rear tires, the steering mechanism, the steering wheel, the pedals and obviously the engine.
Riding Mower Disassembly
To start the lawn tractor it must be disassembled to know which parts will work best.
What you will find is that the rear wheels will require some modification, because wheel hubs are usually built into the rear wheel and require a keyed shaft to turn. No problem, the wheels can be adapted to fit a standard kart axle by simply welding a 1 inch coupler to the wheel hub. The coupler is then held in place with a cross bolt, which prevents the wheel from slipping off the axle shaft.
The front wheels can be removed from the mower, or the entire front axle system can be cut in two and then widened to the desired width of the go kart. Typically the frame width is 20 inches and the wheels are about 40 inches apart.
A good go kart plan will have a simple steering system, so in the end it might be easier to scrap the steering system and use the parts the plan shows. Typically, the plan will allow you to fabricate the steering system from tubes and plates. A good knowledge of a drill and welder is useful here. Save the steering shaft and steering wheel to attach to the kart later.
Go Kart Plan and Frame
The frame should be built using the go kart plan as a guide. A typical flat style go kart will require a flat garage floor for proper frame alignment. The go kart plans I prefer require the side profile systems to be built first and then attached with cross pieces. The side pieces are similar to the girders on a bridge and provide a safety measure that acts as a restraint to prevent occupants from spilling out. Plus, the truss system provides nearly three times the strength of a flat-style go kart. And finally, the truss system gives the kart an aesthetic look or a cool look.
The frame is constructed of 1x1x0.08 square tubing that is cut to proper dimensions and then placed in a pegboard-style fixture to align before welding. The tubes are held in place with 2x4s that bolt to the dash. The 2x4s are placed so the tubes cannot move and are held in place much like building a picture frame. Once the pieces snap properly into place, the tubes can be tacked in and the entire side unit of the fixture can then be removed.
Once the side units have been built, the center spacer tubes can be fitted between the side units and then locked into place as well. Once the entire frame has been tacked down, the entire frame can be welded solid.
Engine Plates and Mounts
The next step is to fit the plates that hold the pedals, the steering gear, the seat stays and the motor plate. If a vertical engine is used, the riding mower engine mount can be cut with a saw. (This will take about 20 patient minutes of cutting. Be sure to wear earplugs and have extra blades on hand. Lubricating the blade helps prevent it from dulling too quickly.)
The vertical motor can then be fitted to the frame around a vertical motor drive system. Some users will try to use a transmission from a lawn mower, however this can actually be quite fiddly, heavy and not wide enough for the go kart you are doing. Others buy a used right angle transmission. The best solution is to use the vertical motor and mount it to the frame without adding a large amount of weight, then adapt the motor to the vertical motor transmission.
Rear axle
The next phase is to assemble the rear axle according to the plan of the kart. The axle is held in place by support plates that protrude vertically from the frame rails. The bearing is mounted in the cutout of the bearing plate. The positioning of this plate dictates where the wheels will be located both lengthwise and vertically on the go kart frame.
Rear axle location is critical to proper weight distribution, which drastically affects steering. This is known as a 50/50 weight distribution. A good go kart plan will take into account weight distribution and the placement of the front and rear axles. Once the rear axle is in place, slide the rear sprocket and rear brake disc into place and then mount the rear tires on the rear axle and check the ground clearance.
Ground clearance is usually about the thickness of a 2×4 for good handling.
The output shaft for the vertical drive of the engine will usually have a clutch mounted on it. The chain can then be mounted on the clutch and rear drive sprocket. This is where I like having a chain tensioner because it doesn’t require the rear axle to move back or the engine system to move forward. A simple roller skate mounted to a hinge system (spring loaded of course) will provide proper chain tension. Be sure to place the tensioner on the slack side of the chain (ie the underside of the clutch system).
Direction system
The next phase is to assemble the front steering system. The front steering system is usually a 1x1x.125 wall cross tube with steering knuckles mounted on each end. I like to mount the head tube with plates so I can remove it. It also allows the steering system to be moved forward or backward. The steering stem is mounted to the cross tube via a bushing plate that is welded to the cross tube. The steering axis is supported by a vertical tube that comes out of the frame itself. This prevents the steering wheel from moving back and forth, up and down, and in and out.
So the steering wheel can be mounted on the steering shaft. The steering linkage is attached to the steering axle plate, and then the linkage is routed to each joint on the front wheel. Make sure the steering system is tight and not loose when complete.
The seat
The next phase is the seat. Usually a wooden seat is built. A cushion is then inserted into the wooden frame. The entire system is then covered with a thick cloth or vinyl material. The cover is held in place with an industrial-style stapler to the rear of each seat. The seats consist of a seat and a back that is tilted up by about 15 degrees. The plates that were mounted to the frame have holes where wood screws can be screwed into the seat backs to hold the seats in place.
mounting of the pedals
The next phase is to put the pedals in place. The key to the pedals is that they snap back into position with the force of the spring. For the throttle, I like to have a spring back when the engine pulls hard so when the throttle is released it slams shut. Same for the brake, I like to have a large return spring pulling back on the linkage.
brake assembly
The brakes can now be put on the frame of the go kart. The major problem with kart brakes is that they float. If they don’t, they will be tied up. The best thing to do is to let the disc float and lock the brake mechanism to the frame.
Bottom plate mounting
The final phase is to place the fitted sheet on the frame of the go kart. This is essential to prevent foot injuries. It provides a lower protector which is essential for kart design. The sheet may be made from sheet metal used in ductwork. The easiest way to mount the sash is to use a self-tapping, self-tapping screw and turn it on with a drill. Space them about 3 inches apart.
final checks
Make sure all the pieces are tight and don’t wobble. Also make sure that the drive system is actually working. And obviously double check that the brakes actually work. It’s a good idea to have a kill switch, which is basically a wire that goes to the tip wire (typically black). When the switch is activated, it cuts the wire to the frame and stops the motor.
The amount of time required to make such a kart is about 7 weekends, if not more. Be prepared for the long haul on this project, but it is well worth it when completed.
