What is This ???

[LouieMCman]

Any ideas?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=250762223125&viewitem=&sspagename=STRK%3AMEWAX%3AIT

[kunzog]

Emergency brake for a Pierce Motorcycle

[rigb]

Looks like the many piles of rusty "crap" I was stupid enough to throw out before I learned. Now I don't throw anything out, ask my wife.

[Pete Gagan]

My guess it is an aftermarket exhaust cutout. The partial pipe slides and uncovers an opening in the exhaust pipe. It would be operated by a pedal or cable. That, I'll admit, is pure guesswork.
Pete Gagan