Topic: Comment on my charging voltages CB500 (ESR240 reg/rec, dyna 5ohm, dyna s)

[paul_D]

I installed a new reg/reg from elctrosport (ESR240)

I'll leave this here. ESR240 wire colour mismatch.
On this ESR240 the brown wire connects to the black regulator wire, and the green wire connects to the regulator white wire, the regulator ground wire is left alone because the ESR 240 is grounded through the block plug. The block plug on the ESR uses 3 white, a red and a black. The three white wires are the coil, the black is ground and red power.
(Source: http://www.regulatorrectifier.com/catalog/1971-1978-Honda-CB750K1-K8F1F2-SOHC-Regulator-Rectifier) *this source saved me from frying it.


My system has Dyna 5ohm coils, dyna s ignition and the new to me ESR 240 Reg/rec replacing the stock components.

My voltage charging test data is as follows:

12.7V   key off
12.5V   key on
12.2V   idle (~1200rpm)
12.5V   2000rpm
13.0V   3000rpm
13.3V   4000rpm
13.5V   5000rpm

I could not get the voltage above 13.5, let alone the 14.5 in the service manual.
I believe the 13.5Vmax is due to the combination of the dyna coils, dyna ignition and the solid-state reg/rec, mainly due to the dyna ignition having a greater draw of ~1A.
But at 3000rpm + i am above the 12.7V of the battery with the key off, so it is charging correctly.

Any and all thoughts welcome.

[Vinhead1957]

I don't think you can go by the 14.5 volts once you changed the rec/reg.   I have the same unit and never checked the voltage. It charges the battery and I ride. Simple as that

[Deltarider]

Is your meter anologue or digital? Some DMMs give funny readings when applied on a motor.

[paul_D]

It is digital. I know what you mean about weird readings. I had it set to 0-20 with 2 decimal places precision and the readings were eradic when I was reading at rpms where the battery was discharging but fine in the charging zone. Switched it to 0-200 with 1 decimal place and it was stable in both conditions. 

[Jerry Rxman Griffin aka MuthaF'er]

You didn't mention what you were getting prior to adding the ESR 240! No comparison to work with.

The 5ohm coils are stock equivalent so throw that factor out. The Dyna S is not a voltage sucker like some others, it's basically a points replacement only. Connectors, connectors, connectors. Clean all and tighten all. Replace any that are questionable or loose. May even replace ALL of them on these older harnesses. Use di-electric grease to protect them from corrosion. Yeah it's a PITA! but do it. Remove and clean the battery ground to the frame. Check your voltage loss at the ignition switch. You can also check voltage loss at the handlebar switches too. Keep it at higher rpms around town. Pull the headlight fuse during the day if needed.

[paul_D]

I don't have voltages from before. Forgot to write them down. But the voltages were below the batteries initial voltage. So it was discharging at all rpms.

I cleaned all of the charging circuit connection and my next thing on my list is going through the loom and cleaning/repairing all the connections. I have the .17 barrel brush for the female bullets, brass brushes, contact cleaner and dielectric.  Just need some time.

I'll add the voltage at the two switches to my to-do list though.

[TwoTired]

The Dyna S is not a voltage sucker like some others, it's basically a points replacement only.

Not for itself, no.  But, it leaves the coils drawing power about 60% more than what a points system does.  Stock points drive coils for 190 degrees of crank rotation.  Dyna-S drives coils for 330 degrees of crank rotation.

[dave500]

have you checked the resistance through the stator and field windings?with the engine running will an average size monkey wrench stay stuck magnetically on the alternator housing?

[Jerry Rxman Griffin aka MuthaF'er]

The Dyna S is not a voltage sucker like some others, it's basically a points replacement only.

Not for itself, no.  But, it leaves the coils drawing power about 60% more than what a points system does.  Stock points drive coils for 190 degrees of crank rotation.  Dyna-S drives coils for 330 degrees of crank rotation.

Thank you. We're not going into ohms, watts, amps and voltage losses at the ignition switch are we   

[TwoTired]

Thank you. We're not going into ohms, watts, amps and voltage losses at the ignition switch are we   

Does it do any good to offer educative info?

[Jerry Rxman Griffin aka MuthaF'er]

Thank you. We're not going into ohms, watts, amps and voltage losses at the ignition switch are we   

Does it do any good to offer educative info?

You'd hope so.... 

[paul_D]

have you checked the resistance through the stator and field windings?with the engine running will an average size monkey wrench stay stuck magnetically on the alternator housing?

I don't know. But I'm trying this next time I'm out.   

[dave500]

its a good trick,switch the key off and it falls to the ground.