Speedometer
Speedometers
Inaccuracy Inherent:
Most bike speedometers are "off" in accuracy. You should test your speedo and odo with a measured mile or with one of the "You are Going XX in YY " radar speed checkers. Or on the Dyno, if you are check / tuning performance or probably most easily with a GPS
Recalibrators: These will recalibrate your speedo to show actual speed. They are available from several different vendors.
Speed Calculator
Yamaha Speed/Gear/RPM Calculator
Speedometer Disassembly / Speedo Face Replacement
How to Disassemble the Speedo to Replace the Face
Speedo bulb replacement
Replacement Bulb - standard #24 bulb, miniature wedge base. any auto parts store will have them.
Hawgstar: To get at the bulbs after removing the speedo: "The rubber has a groove in it that fits a shoulder on the inside of the hole to make it water tight. Just dig your finger nail into one side of the rubber and use a firm steady pull...it'll come...then the bulb just pulls out of the socket...".
Alternative Speedometer Lighting
Forum Thread on LED Replacement bulbs and more
http://forums.delphiforums.com/yamaha1100/messages?msg=45358.1