I did not go that route, the wire between the diode board and the starter motor is the weak link replaced it with 6 ga wire and hi out put regulator now runs at 14.2 volts at 2000rpm. you will have to make the wire your self and will need good soldering skills 

I've never had issues with the stock Airhead alternator. From what I've read the rectifier board seems to be the weak link, and then only due to its physical mounting. Like Chris, I took a different tact that was far less expensive and got much better results.

>> A charging system is exactly like a checking account. If you are having trouble keeping a positive balance, then you have 2 choices: make larger deposits (buy a new alternator) -OR- write smaller checks (start installing more efficient electrical devices).

>> If you are having issues with a dashboard warning light, replacing the alternator simply doesn't make sense. Those 2 items are separated by 3 levels of connectivity ("3 degrees of separation"). It would be like punching my grandson because you disagree with me and then hoping my grandson punches my son, who then might punch me !!

1. First and foremost, replace the headlight bulb with an LED version. The HL bulb consumes more power than anything else in the system. Swapping to LED gives you more light on the road, with at least 1/3 the power consumption. (Most LED HL bulbs require about 25W.) The stock incandescent bulb is 65W, but it was common to install 80W and 100W replacements and these definitely stress the system. What's installed in your headlamp ?

You can also add to this power savings by converting the 2 tail lamp bulbs and parking lamp bulb to LED. You can even get LED replacements for the gauges if you want to go that far. Besides consuming less electrical power, LED bulbs in the tail lamp also increase your visibility to others, which adds to your riding safety.

► Read more here: https://www.airheads.org/community/parts-is-parts/h4-led-replacement-plugnplay-sought/#post-15757

2. The OEM voltage regulator (VR) used mechanical relay contacts. After 50 years these contacts are burned and out of adjustment, and so the whole VR is due for replacement. Bosch (the OEM supplier) hasn't provided mechanical voltage regulators since ~1990. All the modern replacements are solid state. I can suggest the "Higher Voltage Regulator for Airheads" sold by Motorrad Elektrik ( http://motoelekt.com/charging.htm )

In truth, it's the Voltage Regulator that controls the dashboard warning lamp. When you have warning lamp issues, the obvious FIRST step is to replace the device that controls the warning lamp. Especially when you consider that a new VR is less than 1/10th the cost of an entire alternator and installs in minutes rather than hours. 

3. Your rectifier board probably has some very iffy "grounding", which requires investigation. The stock rectifier board is held to the engine cases with 4 mechanical mounts. If your rectifier board uses rubber standoffs at the 4 corners, then the wire Chris talked about in his post is mandatory. If your rectifier board uses 4 metal standoffs for mounting, then you need to insure that there is zero corrosion between the standoff and the board, PLUS zero corrosion between the standoffs and the engine cases. This is best done with the total disassembly of the standoffs and the addition of some anti-corrosion electrical compound, such as No-Ox-Id by Sanchem.

4. Finally, realize that your electrical harness is not 1 wiring system, but 3 distinct ones: lighting, ignition and charging. You can't really be sure the battery is collecting ALL the power made by the alternator until you treat ALL the 50 year-old connectors and contacts within that system with an anti-corrosion electrical compound. 

► Read more here: https://www.airheads.org/community/wrenching/home-mechanic-electrical-corrosion-on-connectors/#post-15811

Hope this helps

What is your idle speed? On my /5, the charge light goes out at around 1100 R.P.M. I think what you describe is perfectly normal. As Richard suggests, lightening the electrical load, and checking the functional parameters of the system is well advised, but if your bike is not idling above 1100, your discharge light will be in play at idle. 

If your bike is a /5 with the original 180 watt alternator, then an upgrade would be worthwhile. My r75/5 has been upgraded to a 280 watt alternator from a '74, /6.

hi 

I agree with everything Richard says I went on stage further and rebuilt whole wiring harness. I wrote an article for Airheads magazine check your back issues. I have a thunder cat diode board very good.

My article is in February 2024 magazine. Hope you enjoy.

Posted by: @8053

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What is your idle speed? On my /5, the charge light goes out at around 1100 R.P.M. I think what you describe is perfectly normal. As Richard suggests, lightening the electrical load, and checking the functional parameters of the system is well advised, but if your bike is not idling above 1100, your discharge light will be in play at idle.

And too: Is it simply the flickering lamp or have you seen any evidence of your battery in a state of low charge ?

Thanks guys! I'll check out the bulbs first. 

Richard, you are full of airhead wisdom!!

@8053 Yeah, my gauge needles are bent and broken, so I can't get an accurate tachy. Need to get the gauges restored!

I did a bit of both, LEDing the headlight, courtesy light, taillight, while upgrading to the Euduralast system for my /6. I'm getting 14V at just a bit above idle, 16V at top. I also added a pair of LED auxilliary lights for night riding (desert roads and crazed wildlife) and wired up a pair of of Buco panniers for redundant brake and turn signals. Magnificent Murph of Eugene said  the Enduralast was overkill until he saw the additionals. So glad I did; the heated jacket is a lifesaver!

16v at top?, I would be concerned about cooking the battery. A new battery with a full charge will have a resting surface charge of around 14.2v. Your alternator is hitting it with 16 volts at highway speed? What is the extra voltage doing? If you ever owned a BSA or Triumph, this is the kind of thing that pops headlight bulbs and boils the electrolyte in the battery's cells.

Posted by: @8053

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16v at top?, I would be concerned about cooking the battery. A new battery with a full charge will have a resting surface charge of around 14.2v. Your alternator is hitting it with 16 volts at highway speed? What is the extra voltage doing? If you ever owned a BSA or Triumph, this is the kind of thing that pops headlight bulbs and boils the electrolyte in the battery's cells.

I feel the same way about the 16V.

Some of the first solid state Voltage Regulators offered for Airheads had an adjustment screw. You were supposed to manually adjust  the system voltage down to 14.2V to finish the installation. This required a voltmeter across the battery posts while running the RPM up to get max alternator output.