On my V65 Lario, when the main headlamp is switched on, the voltage gauge dips far to the left—low voltage.
With headlamps switched off, the voltage gauge remains in the middle or high range; with the parking lamp turned on, the voltage meter still is well within the appropriate green area.
This is where things get odd: With the motor off and the headlamp disconnected, switching the main headlamp circuit on makes the voltage meter dip low (to the left) more than when the parking lamp is switched on. The circuit itself is sucking additional power somehow.
The bulb is a 55/65w H4, but the same thing happens with an older 45/55w bulb.
The headlamp (left side) switch assembly is a new one I got nearly one year ago from MG Cycle.
The fuses are all good and connections clean.
I cleaned intermediate connectors and even re-wired a few things in the past but did not mess with the headlamp circuit.
I added an extra ground strap long ago.
The battery is the correct size and is less than one year old; the charging system works properly.
I thought the voltage gauge might be the problem, but after a 1.5 hour ride this morning with the main headlamp on, the battery did not have quite enough juice to turn the starter without a friendly tap. Normally, the starter spins easily. Empirically, it suggests that the headlamp sucked a bit more juice than it should.
Has anyone experienced similar headlamp circuit strangeness with small-blocks?
