Ask The Editors: Can An Electrical Issue Make An Engine Feel Mistimed?
Ignition troubles can result in a lot of oddities.
While you suggest the machine ran fine prior to changing out the voltage regulator, that leaves the obvious question: why would you replace the voltage regulator in the first place, then?
We suspect an ignition problem likely resulted in you testing and replacing parts and it sounds like that same ignition trouble is haunting you still. Assuming you cannot swap back to the original voltage regulator to see if it solves the problem, our best guess would be to test and consider replacing the CDI box itself, as a faulty unit could duplicate the symptoms of a mistimed engine (as, after all, it is determining the frequency of electrical discharge to provide spark).
To test, remove the CDI box, grab your electrical multimeter, set it to ohms (resistance) and place a lead upon each of the terminal prongs. Your results should come in between 0.5 and 2 ohms of resistance. If you’re outside of this range in either direction, you’ve found the culprit.
If you’re unsure which of the terminal connectors to touch for an accurate reading, here is a video that should help:
