The tach on my 92 1100 seems to malfunction. After about 6500-7000 rpm the needle dances all over the place, especially while under acceleration. I am running the Dyna 2000 Ignition System. Cruising on the highway at steady speed, it is just fine, so I know the wiring is correct. Has anyone been able to "fix" one of these things? Or can anyone recommend a quality aftermarket unit that will fit in the stock location? Thanks in advance for any assistance.