Firstly, I admit that I did not see or hear much of the video, But I thought it unusual to have cylinders 1 & 2 sharing a carb, likewise 3 with 4. Earlier twin cylinder Hondas only shared a carb if they had a 360 degree crank because the intake and exhaust pulses were evenly spaced giving smoother breathing. Bikes like the CB72/77 and the later CB250 K series had twin carbs because they were fitted with 180 degree cranks which give uneven pulses. The way the video shows the carb fitting means that each carb is supplying a pair of cylinders which are 180 degrees apart. Many years ago Mick Hand sprinted a 250 supercharged Honda which was catalogued as a CB72, but it had a C72 crank fitted to obtain the regular intake pulses.
