rice n 1. a modified, imported Japanese car. ("Well I hear a lawn mower on steriods, must be a rice!")
rice-rocket n 1. any sport motorcycle or replica of a race motorcycle, usually Japanese in origin. ("Mongo kicked over that nerd's rice-rocket last night.")
Slang mate, its a slang! If u want more such slang, check this one out...
http://www.ocf.berkeley.edu/~wrader/slang/r.html