I have purchased a used 2006 Stratoliner with 26k miles. I have observed that sometimes upon start-up, that the speedometer does not work. The rpm and gas gauge does. After driving around for 15 minutes or so it just starts to work again.
Any do-it-yourself recommendations fro troubleshooting?
The easiest check is to remove the instrument cluster from the gas tank (about 2 minutes with an allen wrench--BE CAREFUL not to do any French carving on your gas tank while you work!). Check to make sure the wiring connections are tight.
Most likely you are afflicted with what happened to me: moisture inside the instrument cluster, either from washing, rain, or condensation. Even though it may not be visible moisture, it will cause precisely the symptoms you describe. With me it was an intermittent speedometer and an intermittent fuel gauge, sometimes simultaneously, most often not. The tach never had any symptoms.
The really bad news about all this is that there is no cure other than replacement of the instrument cluster, and that's $800 of beer money down the tubes...
The root of the problem is that the instrument glass was not properly sealed at the factory. My dealer found that out and replaced the instrument package under extended warranty. He did say Yamaha was "aware" of the problem. Depending on how you and your dealer doubleteam Yamaha tech support, perhaps you can convince them to do the honorable thing...
In any case, check the wiring connections first and burn joss sticks that you only have a loose connection.