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I am having a charging issue with a low mileage 1974 CB360 that I restored. One of the Ignition coils was bad and I replaced them with 2 new coils that are 3ohm.

I have done stator testing and voltage testing with and without the regulator. The Rectifier was replaced with new, the regulator is original as is the stator. I am unable to get over 1amp charging which led me to start checking from the stator on up. The bike is totally stock with no changes in lighting. My Honda Mechanic friend believes that the 3ohm coils are drawing too much amperage. We measured 6.6a. To test this, I ran the bike on one cylinder with one coil unplugged. There was a corresponding improvement in amperage.

My question, anyone every run into this? My testing and values are below:

AC Voltage Tests: Test done with stator wire unconnected to main harness

Test wires Coil Resistance IDLE 4k 6k
Pink-Yellow (4 coils) 1.4 Ohms 12v 40v 60v
Pink-White (2 coils) .7 Ohms 9v 37v 53v

Voltage Charging Tests: Tested with and without Regulator connected

Position IDLE 4K No Coils
Key OFF – Battery 12.34v
Key On- Lights Off 12.33v 13.3v 6
12.7v 2
Key On-Lights On 11.90 12.28 6
11.92 12.04 2

Also tested charging and output with different Rectifier – No Change

I have pretty much confirmed that the coils should be 5 ohm as the factory spec. From what I read, 3 ohm coils can provide hotter spark and some use them with electronic ignition.
 

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Is that battery fresh off the charger? I'd look there first, anything under 12.6v is usually a bad battery. These bikes run badly with a weak battery.

Also, why do the rectifier without the regulator? The old R/R setup, just due to the materials available, is less efficient than modern alternatives. Sparck's combined R/R for Honda twins runs $35.
 

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I had this on a CB400F. I ran 3 ohm coils and the bike ran fine but the battery continually died. I had cleaned all the connections and checked all the components several times. Once I switched coils to one's with stock values the charging system worked 100%. Less internal resistance = more power leaving the battery.
 

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Low ohm coils are for a specific type of ignition and will run hot even if they don`t burn out.
6+ amps is way too much `draw` and is putting wiring harness under stress.
You don`t need a lot of charge amps.
As long as you have more `going in` than your taking out a `load balanced` system `wastes` less engine power. The electric starter is the largest load on battery, usually around 50~60 amps when solenoid contacts close then 35~40 amps spinning motor. Realistically, you need to ride about 30 miles to compensate for one cold start
 
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