Re: what did you do to your motor bike today?
The speedometer going back to 0 once it gets to 30, not sure what that's about. But the computer resetting itself is caused by interference, either from the cdi or the plug wire, or by having too many things grounded to the frame. I always had problems with the cycle computers, didn't matter if they were wired or not. One would just reset itself once in while, another would do it just about every day. One got completely fried. One I had last year acted a little wonky, but nothing serious until I installed a brake light. The brake light was grounded to the frame, and every time I squeezed the brake lever, the speedo would give a speed reading, but when the brake light was off, it stayed at 0 no matter how fast I went. Too many grounds to frame will create just enough of a magnetic field to confuse the sensor. I recently switched to a 4 stroke, and bought another cycle computer hoping that there wouldn't be so much interference. I was wrong. Installed it after work one day, and when I left for work the next day, the speedo constantly reset itself. I have a handlebar mount for a smartphone, so now I use that as a gps speedo, and its pretty much guaranteed accurate compared to a cheapo cycle computer.