Back in the early days of motorcycling, manufacturers didn’t just do a promotional video of the final product as it was being ridden down the highway as convincing as that might have been for the rebel riders of the time. Instead, they would have taken the viewer (and possibly future customer) through the entire building process so that they knew what they’re machines were made of.
This is an Indian Chief promotional video from their factory in Springfield, Massachusetts. At that time, there were no automatic assembly lines that would take care of at least part of the building process so it was all done by dedicated Indian workers.