Reb

Has anyone had a VERIFIED Ignition Pulse Generator failure, and what were the symptons ? The manual states 0.7 volts minimum. Mine puts out 0.642 and I have a backfire/bogging down problem just off idle at about 1800-2000rpm through the front cylinder. Would this mean the ICM is not getting the correct message and not advancing the timimg??? thus causing the cylinder to fire at the wrong time when the intake valves are still a bit open. But why only the front cylinder. If the IGP is stuffed, would'nt it cause both pots to misfire.

gboezio

It could a carb problem like a clogged pilot jet since it sounds like a lean backfire (flame dwells in cylinder from slow burn lean mixture).
Honda have set a minimum of 0,7, but the ICM is capable of reading less than that, witch is probably your case.
Maybe take sample at different RPM to see if the voltage rise, if it hits a low spot at those RPM, it could be faulty, Fist tooth fires one cylinder and first missing fires the other, I suppose that it's possible that it catch one event but not the other and fires too early or too late since it fires twice per cycle, just before the intake opens, so if it's late by 30° (one tooth) or more on the wasted spark cycle it could ignite the intake charge and blow it back into the airbox.
The timing advance is controlled by the ICM using the TPS input, it would affect both cylinder at once tough.
But make sure the carbs are healthy first.
Try it with the choke on to see if it helps at all.

RickB

You can try to pull out the choke a little to richen up the mixture and see if it runs any better... If it does check the carb like gboezio suggested.

Springbubba