[750Devo]

Hi, I have a magneto fired motor with an alternator charging system. 32 amp charging system with a stock Harley voltage regulator. No battery, or capacitor.

lights work great at idle. As soon as rpms come up lights dim out heavily. Gets worse as rpm goes up.

I suspect I need a new regulator. It was off a 1990 Fxr that was working fine, but before I start changing parts I thought I would check in here to see if Im missing anything obvious. This is my first time running this particular setup.

I ditched the stock stator plug and hard wired the regulator to the stator. I thought I kept the wires connected in the same orientation as they would be If running the stock evo plugs. My assumption being it should not make a difference either way, but It is possible I got the two mixed up. Could this cause the issue?

Any input appreciated.

 

[Ducbsa]

Since the alt is AC, swapping the leads shouldn't cause any problems.

 

[joe49]

Have a look at the bottom of the regulator. Your looking for burning of the epoxy. Burning = bad. You will also need to check the Stator. Check your manual for ohm tests. Then you can test for volts or just use a 120v incandesent light bulb, the bulb should get bright as you increase rpm, and will be dimmer at idle. Since you're not running a battery,you will need to set up a nurse battery to run the engine for the voltage tests. As a note there is enough voltage from the stator to kill your ass. My thoughts on no battery or condenser is it wouldn't last very long under road use, as the regutator is forced to shunt a lot more voltage. Before everyone gets their panties in a bunch, because they have it that way. Road use means hours on the highway, not bar hopping.

 

[750Devo]

Since the alt is AC, swapping the leads shouldn't cause any problems.

Thank you, that is what I suspected.

 

[750Devo]

Have a look at the bottom of the regulator. Your looking for burning of the epoxy. Burning = bad. You will also need to check the Stator. Check your manual for ohm tests. Then you can test for volts or just use a 120v incandesent light bulb, the bulb should get bright as you increase rpm, and will be dimmer at idle. Since you're not running a battery,you will need to set up a nurse battery to run the engine for the voltage tests. As a note there is enough voltage from the stator to kill your ass. My thoughts on no battery or condenser is it wouldn't last very long under road use, as the regutator is forced to shunt a lot more voltage. Before everyone gets their panties in a bunch, because they have it that way. Road use means hours on the highway, not bar hopping.

I will test the stator, that is a good idea. No problem keeping engine running as it’s magneto ignition.

if Stator tests out ok I will probably get a cycle electric regulator that is designed specifically for mag fired bikes with no battery.

just wanted to see if I was maybe missing some obvious before I start changing out parts

thanks

 

[750Devo]

Solution to this one was to add a capacitor. Problem went away. Hopefully this will help someone else.

 

[govmule84]

Doc Benway went through this years ago and came to the same conclusion. Stuff a cap inline.