Some errors:

1, "45 Degree Offset." Harley's Vtwins are radial not offset. IE They use the Knife and Fork piston rod design(Slave and Master rods like a Radial engine uses).

Honda Yamaha and basically everyone else uses the Offset design.

Only S&S and Harley use the radial design.

2, The Plop Plop sound? We call it Potato Potato.(Nit picking, I know)

3, 20,000 number is for Harely only, it was supposedly reported that Indian provided 50,000 bikes.

It was a total of 70,000 motorcycles provided during the war.(between them)

4, Harley's first OHV engine and also 8 valve engine was in 1916 not 1936, but it was only a racing engine. Here's a video of this engine in action: https://www.youtube.com/watch?v=hedv8RGcvMQ

5, Flatheads used Pushrods. I dont know why he said they don't. That's what those fat tubs are on the side of the cylinders are for(that go from the crankcase to the head).

6, (nitpick) The sportster is the origin of the Sport bike as a whole, not the super bikes. Superbikes would come later from the Speed wars of the 80s and 90s between Japan and European sport motorcycles and the racing of production motorcycles.

Sportster represents the beginning of the sport designed motorcycle class.

7, "hardly drivable" It's "hardly-able, son."(nitpick)