It's been raining non stop for a week here in Blighty and I sat through the whole sorry saga. I even commented to him about getting the thing rollerised, which he does mention later on but decided not to bother.
If you look closely he has mounted the air filter housing under the seat where it will fill with water the first time the bike is ridden in he rain.
There is a Youtuber called Delboy here in the UK who has inspired the incompetant to hack about perfectly good bikes in the name of 'customisng', that guy certainly has a lot to answer for.