What drives the speedo?

Posted by MarkPBG on May 08, 2013; 4:55am
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/What-drives-the-speedo-tp4040468.html

Is there a plastic gear like on cars that gets worn out. My speedo isn't calibrated, and when riding it, I notice the MPH occasionals jumps around. I'll maintain a constant speed, but the speedo which was reading a steady 40MPH, suddenly jumps to 50MPH, then back down to 45, so basically, I'm not really sure how fast I'm going.

What should I look for as far as adjustments, or parts that wear out that may cause this (like a plastic drive gear?)

Thanks for any help. :)