Harley-Davidson Inc. has asked the Government to trademark a roar -- the one its motorcycle engines make.

A spokesman for the Milwaukee-based company, which has been manufacturing engines since 1909, said on Friday that wannabe competitors were trying to mimick the full-throated growl, threatening to undermine the motorcycles' value and re-sale price.

"We are looking to register the sound of a Harley-Davidson motorcycle -- the sound of a V-twin engine with a single crankpin," said the spokesman, Ken Schmidt. "We're not talking about the sound that comes out of the exhaust pipe. You can alter that sound, and many of our customers do."

Trademarking a sound is not unprecedented. NBC did it with the three chimes that signal its name. And MGM did it with the lion's growl that has opened countless movies.