Hi Tiedie and all. First thank greatly for the resistors but as it turns out I didn't need them. I had already carefully cleaned and lubed the speedo. Hardest part is getting the bezel on and off but ultra sonic clean and reassembly went well. As far as the bouncy tach I like you went through all the contact points and cleaned them up and a new smear of dielectric grease (Dow Corning 4 Electric Insulating Compound) This is from Snowbum's excellent article on electronic tachs.
"Problems in bike's wiring &/or in the ignition circuitry; even some green corrosion in the ignition coil towers or kill switch, etc., can cause weird readings ...be sure those are not the problem! Only good way to be sure the KILL switch is not at fault is to bypass it, temporarily ....although if cleaned, and then symptoms gone, you found the problem. Green corrosion is particularly annoying and problematical, as it can help create a 'diode effect'."
There was a bit of corrosion on the coil connections but my last stop was the kill switch. Took it apart and beside a dead bug there was a good deal of green corrosion on the copper disk meeting with the steel spring. 30 years in a shed took its toll. Cleaned it all up as above and yesterday went on a 50 mile test ride. Tach and speedo were perfect! As new, solid and not a hint of wobble. Call me a happy camper.
