The Motorcycle's electrical system isn't as noisy as a car's and doesn't have all the current / voltage spikes as in a car.
The motorcycle generator's voltage varies with RPM's and also with the current battery state - ranges from say around 10 - 14.5 vDC.
9. I am told to use a series resistor to limit current after an in-line 1amp fuse - what value and power rating fpr the resistor?
I also read I might need to provide a separate voltage regulator to step down from 12 vDC to a lower voltage to avoid overheating the arduino's power linear regulator?
14. For the 12vDC monitor, the gear position, and the engine coolant temp monitor, I am planning to use just a simple resistor voltage divider to rescale the analog voltages between 0-5vDC?