Motorcycle Repair: Yamaha problems, yamaha yzfr6, digital speedometer

Question
I emailed one of you once with a question about my bike. and you answered. I can't remember who it was. But if it wasn;t you I included my first question again. My first question was this:""My 2001 Yamaha YZFR6 has approx 10k miles. I had a new rear tire put on recently, and very soon after that anytime I hit a bump my digital speedometer will fluxuate. I took it to the local cycle repair shop, they checked the sensor under the gas tank, and said the chain has to much slack and removed a link. The probelm soon returned after a couple of hours. Then all of a sudden the gas light comes on and registers on screen as if I was in the reserve tank. I went to the gas station filled up, and then about 15 miles later the light came on again. What would cause this. I am unsure if the new rear tire placement even has anything to do with it, but that is when it started. Is a fuse loose or going bad, a ground wire loose, or what. It seems as if the bike is riding a little rougher, but I don't know if I am really over examining it since the other problem.";
And since then I drove the bike to a repair place, upon arrival I turned off the bike to talk with mechanic and proceeded to turn on the bike and show the mechanic nothing happened. No lights, no turn over of starter if there is one, no hesitation or anything. Does it sound like my first problem is tied into this second issue, weak or now dead battery causing the fluxuation, or completely seperate and more costly issue. Thanks Sorry to ask you again. "


Answer
Hi Polly.

I don't recall your previous issue, but I can tell you that what you have is an electrical short (one or more).  Unfortunately, many Yamahas have electrical issues like that.  I have had a couple like that.

Start with the ignition switch and main power circuit wiring.  That includes the fuses and fuse connectors (including the main fuse).  That is the big worry.  Don't check the fuses visually.  Use a multimeter and see if they are good that way.

Now you should also check the charging system by checking the charge on the battery while the bike is running.  It should be charging at between 14-16 VDC.

Start with that and see what you find.

Good luck and ride safe.
FALCON