Going by the preliminary design I created in CAD I have been designing the rear drivetrain assembly of the power wheels kart with the twin alternators as motors. 

This design took me longer, as I needed to first see where the alternators would fit in a position that would allow them to be friendly to overall weight distribution, as well as negating the possible torque difference from each motor as much as possible. 

I also decided to place the batteries we would be using underneath the driver's seat for a lower center of gravity and better weight distribution.  Most of the design came about by trial and error and eventually led to the current design I have.  Some of it I ballparked first by placing components on the ground for a rough estimate for a design idea, and then I would translate it to the software to see if it was a good design. 

If the design was not to my liking or would not be feasible then I would rearrange the components until I found a design that I liked.  Once I had a good placement for the batteries and the alternators I would then place the necessary components around them that we needed, such as the position of the brake disk and caliper, bearing hangers, and seat. 

Most of the components I had to design myself to accurately represent the space they take up as well as determining accurate mounting positions.  Parts such as the brake disk, brake calipers, seat, sprockets, wood bumpers, alternators, axles, bearing hangers, brake disk hubs, wheels, and tires were all modeled by me in the software by hand as there were no online resources for these components.  Even the metal tubing that I am going to use for the chassis had to be modeled by hand, with specific dimensions for each piece. 

Here are a couple renderings showing the rear drivetrain assembly for the go kart:

The design is still not finished however as I still need to add things such as bearings, wheel hubs, and chains. Those things are negligible though, as this current design and placement is very accurate even if I do not model everything exactly.  Due to the nature of the software,  it allows me to create tolerances and space in between components which represent the space and tolerance needed for those specific parts I have not created yet. 

The next steps for the design will focus on the front end of the go kart. This will include modeling the front steering column, spindles, and steering wheel.  Currently I have the front wheels and axles in place for measurement purposes, but these are more placeholders for the full steering assembly.