The Bureau of Transportation is offering motorcycles a monthly metered parking permit that allows motorcycle or moped parking in any metered on-street space for the designated time limit indicated by the parking meter without payment of meter fee.
The new pilot permit program, launched September 1, 2010 costs $40/month. The Bureau will monitor the program and make adjustments as needed before adopting final rules in August 2011.
Here is a link to the application for the new permit, http://www.portlandonline.com/transportation/index.cfm?c=36173&a=314369
The permit should be attached to your license plate with screws, and must match your license plate number exactly to be valid.