Honda Hornet
Member
I have been trying to get my 1978 Honda CT90 K9 set up for long distance riding (Bellingham WA - Los Angeles CA) this spring. The problem I am having trouble addressing involves the 6V electrical system. I have a silicon rectifier that produces sufficient DC voltage, but I either have lower voltage for the ignition coil or lower voltage for my LED tail light, while having too much for recharging the battery (resulting in a loss of water in the flooded lead acid battery after long rides). I bought a new flooded lead acid battery in Aug 2023 and it seems to function well and accept and hold a charge (typically 6.2-6.5V) before I start the bike in the morning without needing to use a charger.
As far as I can tell my bike has original electrical components, except:
-6V LED gauge lights and tail/brake light
-New flasher relay that also worked for 12V turn signals (to eliminate the flasher relay as the source of the lower voltage, I removed it and there was no change to my measurements).
(Headlight and turn signal bulbs are original, and I have made no changes to the generator or ignition components).
This is confusing to me, so let me tell you what I have been measuring. For quite some time I have had a multimeter measuring the voltage at the battery, but I recently bought a small digital voltage gauge from China. As the voltage gauge does not have a power switch I wanted it to be connected to the power that turns off with the key (the black wires inside the bucket). What I did not expect is that the voltage of these wires was much lower that at the battery. As examples, when the bike is not running and the key is on the battery is 6.4V and the black wire is 3.7-4V. when the motor is running the battery is 7.2V and the black wire is 4.7V.
I have tested that there is no resistance in the wires between the battery terminal and the black wire when the key is on, and the key switch is effective is disconnecting all power when the key is off.
Is this degree of lower voltage common?
As far as I can tell my bike has original electrical components, except:
-6V LED gauge lights and tail/brake light
-New flasher relay that also worked for 12V turn signals (to eliminate the flasher relay as the source of the lower voltage, I removed it and there was no change to my measurements).
(Headlight and turn signal bulbs are original, and I have made no changes to the generator or ignition components).
This is confusing to me, so let me tell you what I have been measuring. For quite some time I have had a multimeter measuring the voltage at the battery, but I recently bought a small digital voltage gauge from China. As the voltage gauge does not have a power switch I wanted it to be connected to the power that turns off with the key (the black wires inside the bucket). What I did not expect is that the voltage of these wires was much lower that at the battery. As examples, when the bike is not running and the key is on the battery is 6.4V and the black wire is 3.7-4V. when the motor is running the battery is 7.2V and the black wire is 4.7V.
I have tested that there is no resistance in the wires between the battery terminal and the black wire when the key is on, and the key switch is effective is disconnecting all power when the key is off.
Is this degree of lower voltage common?