Yanmar diesel 2WD hydraulic drive motorcycle

Here’s a short video of a neat diesel motorcycle I saw at the Barber Vintage motorcycle show. It’s built from a Yanmar 10hp diesel coupled to a variable displacement pump. Then out to hydraulic motors to turn the wheels. Looks are deceiving. There’s a lot of aluminum parts to the bike. The bike only tips the scales at 300lbs. The bike can be ran in 2WD or single rear wheel drive. Speeds are about 25mph in 2wd, and 55-60mph in single wheel drive. Fuel estimates are around 100mpg! This is due to the