I recently installed a Pertronix Ignitor electronic ignition in my Speedster. The Tach. under read by 800rpm at idle.
The engine runs just fine. Pertronix advised to install a capacitor and gave me the correct specs. The capacitor had no effect. I put the points and condenser back in and the Tach reads correctly. The coil has 3.0+ ohms resistance.
Any ideas or suggestions?