"I would like... if I may... to take you on a strange journey..."
To say that Bōsōzoku (暴走族) and Yanki (ヤンキー) gangs are a "nuisance" is something of an extreme understatement. Bōsōzoku are notorious for riding their highly (and often illegally) modified motorcycles up and down the streets of both major metropolitan areas and smaller cities revving motors, honking horns, swerving in and out of traffic, swinging baseball bats and iron bars, abusing pedestrians and motorists, damaging property, and essentially being a menace to anyone and everyone they encounter.
Bōsōzoku and Yanki gang members are typically between the ages of 15 and 20, the years in which you can ride a scooter or motorcycle, but not generally drive a car. They have never been adult oriented groups like the so-called "outlaw" motorcycle gangs in the West. They are very much a teenage youth sub-culture, unique to Japan!
But who are the 'Bōsōzoku'? ...and what is a 'Yankī'?
It is an over simplification to just say that these youths are from lower-income situations and broken or abusive homes. The fact is, they are the "square pegs" in Japan's "round holes." They represent, by their very existence, evidence of societal ills most in Japanese society would like to quietly pretend do not exist.
The Bōsōzoku and Yanki themselves would no doubt argue their cultural value in different terms, portraying themselves as protectors of Japanese traditions which have been abandoned by mainstream society, and see themselves samurai with "yamato-damashii".
Many Japanese are extremely reluctant to talk about Bōsōzoku and Yankī in detail to a Gaijin (外人, literally "outside person" meaning "foreigner"), and as a result, most pages in English dealing with the subject are full of inaccuracies and half-truths. This is especially true when it comes to Bōsōzoku as they seem to be considered as a source of embarrassment, even almost a source of shame, to many Japanese.
This is perhaps not so hard to understand when one considers that while here in the West personal individuality is something that is not only idealized and sort after, but is actively encouraged (at least to a point) and often is celebrated, but in Japan conformity is the social norm.
This site represents what I have been able to glean from talking to Japanese about these particular youth sub-cultures that have, for the past 40+ years, steadfastly refused to be 'hammered down', and why, as disdainfully as they are regarded by mainstream Japanese society, Yankī and Bōsōzoku sub-cultures have still become a prominent part in Japanese Pop Culture through Manga, Anime, TV and Movies... and why they are such an object of fascination to a Gaijin Raidā (外人ライダー "Foreign Rider") like myself!