It's not so much that I hang out with bikers, more that I am one. I've been in the wind for a quarter century, I've been riding Beemers (BMW) for more than a decade, rode a Harley for ten years before that, and have never heard the term "Brat rocket". 'Schnitzel burner' yes, brat rocket no.

The only words I have heard rocket appended to are rice and crotch. Rocket does not designate racing bikes, it merely indicates the performance capabilities of ordinary Japanese street bikes. (Way back in the day, as the saying goes, Birmingham Small Arms, BSA, produced the Rocket 3.) The Kawasaki H1 and the Yamaha RD were known as "crotch rockets" long before the more recent vogue of radically race-styled machines. I also worked for a branded Big 4 dealer and in independent bike shops for alost 10 years, so the cant was my everyday language.

I don't think that "rice burner" had anything to do with the fuel allegedly used in the machines - certainly they never used rice based alcohol fuel in this country. I believe it was just your ordinary racist perjorative.