The next step in building a go kart is to weld the motor mount to the frame. This guide will show you how to line up the clutch and drive wheel sprocket, then weld the go kart engine mount in the correct spot for future chain tension adjustments.
Assemble the Drive Wheel and Mount it to the Kart
The go kart drive wheel assembly is what is used to move the kart, and to transfer braking force to the ground. The assembly should be assembled as follows:
- Insert two bearings into the drive wheel, one on each end.
- With the drive wheel laying on its side, insert four 5/16-18 x 1 1/2″ bolts through the go kart drive wheel hub.
- Insert the 60T 420P sprocket over the four bolts, and secure it by threading four 5/16-18 nuts to the bolts.
- Insert the 4″ brake drum over top of the bolts, and secure it by threading on an additional four 5/16-18 nuts to the bolts.
- Slide the drive wheel over the driver’s side stub axle, and hand tighten the 5/8″-11 drive wheel nut to secure the drive wheel assembly to the axle. Spin the wheel by hand, it should continue to spin without binding. If it stops abruptly, loosen the nut. The sole purpose of the nut is to keep the drive wheel from sliding back and forth, not to be tight.
Install the Go Kart Clutch on the Engine Shaft
The clutch will slide right onto the engine shaft. Align the 3/4″ bore go kart clutch to the go kart axle. Make sure you put the 3/16″ key in the clutch, then slide it onto the shaft. A 5/16″ flat washer should be inserted over the end of the engine shaft and a 5/16-24 (fine thread)x 1 1/4″ bolt is typically used to secure washer and clutch to the engine shaft for most 5-7hp 3/4″ shaft engines(e.g. harbor freight 212cc engine used here). Some clutches come with threaded holes for set screws as well. If your clutch comes with holes for set screws, use an Allen wrench and set screw(s) to secure the clutch to the shaft.
Mount the Engine to the Plate
The go kart engine mounting bolts are 5/16-18 x 1 1/2″ bolts. Insert all four of them into the motor mount, and secure them with the four 5/16-18 serrated flange nuts. Make sure you have the engine slid rearward on the slots. As the chain stretches over time, you will need to move it slightly forward so it is important that the engines default position provides for maximum travel forward.
After you have the engine secured to the go kart motor mounting plate, line up the clutch with the drive wheel sprocket with a straight edge. The face of the sprocket should line up with the face of the clutch’s drive sprocket.
Cut and Install the Chain
Lay the chain across the drive wheel sprocket and the clutch sprocket. The chain that comes in the go kart parts kit is a few links too long, so you will need to shorten with your angle grinder. I marked the link that needed to be cut out, then cut off the top of the pin and link, then removed it with a hammer. I did this all from a bench vise. You can also remove pins with a small nail and hammer, or a special tool called a chain breaker.
Once you have the chain cut to length, insert the master link clip. I wrote an article about how to install a master link clip if you aren’t sure how to do it.
Adjust and Tack Weld the Go Kart Motor Mount
It is important that the engine shaft is parallel with the axle shaft, and that the go kart motor mounting plate is positioned forward so the chain is just a tiny bit loose. Once you have the mounting plate adjusted, clamp it down with four c-clamps, and tack weld the plate on the four different corners that sit on top of the frame.
Weld the Go Kart Engine Mount to the Frame
After you are absolutely certain that everything lines up between the engine, chain, drive wheel, and seat back, then weld the go kart engine mount to the frame. I saved this step as the last weld before painting after I had already test driven the go kart.
Now that you have the go kart motor mount installed, you are one step closer to finishing the kart! Lets move onto the next step, the seat.