As far as I know, most of the R bikes on the road today still have the OEM alternator. Those that do get replaced are because users either needed extra lighting (pre-LED), or wear heated vests, pants, and other winter apparel so they can ride year-round. So most of the replacements you read about are based on load requirements, not age. 

• The highest wear item by far are the 2 carbon brushes. If you have not changed these, then that is highly advisable and will set you back a whopping $6 or so. 

• The second highest wear item is the bulb behind the Alternator warning lamp on your dash/ instrument cluster. It must be an incandescent bulb and it must illuminate in order for the alternator to operate. 

• The third most common failure item is working its way up in the standings, and that's the Voltage Regulator (VR). The OEM unit worked great, but it's mechanical in nature, with swinging arms and contacts to burn out. Advanced age is simply taking its toll. All-electronic regulators (with zero moving parts) have been on the market now for 20 years. Because the Airhead VR is also common to VW, Porsche, Volvo, and 20 other automobiles with Bosch charging systems, you can now buy an all-electronic replacement starting at $12 for standard batteries. Even your local NAPA store has them. I highly suggest you replace your OEM unit as "proactive maintenance". Example

• The forth most common failure is the rectifier board. These die due to handling too much power and/or lack of air flow; in other words too much heat. Reduce the power you're using and the heat will be lowered.

If you want to extend the life of your alternator (and total charging system), then simply REDUCE the electrical load. Besides replacing the failure points listed above, the best thing you can do is replace your headlamp and tail lamp bulbs with LED substitutes. That will cut the power load from about 80W to well under 30W. That's a reduction of 62% (~3-1/2A less) through your rectifier, and "frees up" more power to charge your battery on short trips. (BTW, that's also a 62% reduction in rectifier board heat.)

So IMHO the alternator itself is rock solid, it's the supporting parts of the charging system that need your help. Especially at this point in their careers, when they are operating 15 years beyond their design life. 

Hope this helps.

Thanks heaps for the great info...I have a couple of questions...you said I needed an incandescent indicator bulb, but I recently changed my instrument board to an LED board (the kind that is advertised in our magazine) how does that affect it since I no longer have an incandescent bulb there, for the indicator still seems to be working nominally...

The only additional voltage draw are the little Wixom bag lights...that's it, in addition, I use Odyssey batteries and I try to keep it topped off with a battery tender.

Thanks for the ebay example, but I noticed it said it was 24v regulator...is that what I should be looking for?

I will be ordering brushes forthwith!

Jim

Posted by: @10385

Thanks heaps for the great info...I have a couple of questions...you said I needed an incandescent indicator bulb, but I recently changed my instrument board to an LED board (the kind that is advertised in our magazine) how does that affect it since I no longer have an incandescent bulb there, for the indicator still seems to be working nominally...

The only additional voltage draw are the little Wixom bag lights...that's it, in addition, I use Odyssey batteries and I try to keep it topped off with a battery tender.

Thanks for the ebay example, but I noticed it said it was 24v regulator...is that what I should be looking for?

I will be ordering brushes forthwith!

Jim

 

Jim -

All good points...

• No need to worry. Your Katdash instrument board has a resistor made into the alternator warning lamp circuit that adds the required resistance. Several outlets also sell a discrete resistor you can solder into the harness in case the bulb burns out. I was discussing "completely OEM" setups.

• It's not the physical size, but rather the number of bulbs X the wattage that matters. Superbrightleds.com probably offers replacement LED bulbs for that location.

• Odyssey batteries are AGMs and require a higher charging voltage than most charging circuits and trickle chargers are set to deliver. Please read the paper that came with your battery. Therefore you'll need the higher output VR offered at http://motoelekt.com/charging.htm   

• No, my bad on the 24V VR, it needs to be 12V. I simply rushed over to Ebay and copied the link to the cheapest Bosch-type VR to make my point. But since you have an Odyssey AGM battery, you wouldn't want even the 12V version of that.

@wobbly Thanks once again for the awesome education! (I love learning!) I'll budget the omega system in...that way I can provision for my heated clothing on this bike also! I am going to replace the H4 with LED, as well as some of the other bulbs.

Thanks for your interest and help!

PS: My Odyssey battery is six years young, and I have no idea where the paperwork is 🙂

Jim

Just to add to Wobbly's comment - I put the Omega system in my 91 R100RT. It has been one of my better decisions. Heated vest, heated gloves, extra lights and no fretting or obsessing over the V meter. I also changed the headlight bulb to LED and I am pleased with the improved visibility. 

Craig

Posted by: @10385

@wobbly PS: My Odyssey battery is six years young, and I have no idea where the paperwork is 🙂

Jim

Then go to their web page and read. Or call and talk to them.

@wobbly too simple...no wonder I didn't think of it... 🙂

Which LED headlamp are folks using.

Thanks.

@epidoc this was recommended...Superbrightleds.com

Posted by: @10385

@epidoc this was recommended...Superbrightleds.com

► I recommend SuperbrightLEDs.com for all Airhead lamps EXCEPT the headlamp bulb. 

Of course they offer an H4 type LED bulb for motorcycles, but IMHO it's not an optimal replacement either for seeing at night OR daytime safety. The problem is that their bulb is based on a FLAT substrate (IOW 2-sided). One side (~160°) illuminates for Low Beam, and both sides (~320°) illuminate for High Beam. While a device mounted to a flat substrate is cheap, the generated light does not give the best night time pattern OR show as fully illuminated for on-coming drivers during day or night.  

► The better H4 replacement LED bulbs incorporate a 3-sided (equilateral triangle) construction. On Low Beam, 2 of the sides illuminate, but the coverage overlaps and so a full 240° of the reflector is illuminated. On High Beam, 3 of the sides illuminate. This full coverage results in a much better pattern for night time riding AND full 360° reflector illumination for better daytime safety.

►►You will also get better results from your H4 LED if you'll remove the sub-reflector from the headlamp reflector/glass assembly.

Hope this helps

@wobbly Thanks for the clarification. Is there an H4 LED bulb manufacturer that you would recommend?

@10385

There is not a single manufacturer, there are numerous versions available and the part numbers seem to keep changing. Therefore, I think it's much more effective to highlight the desirable features you want to look for when buying an H4 LED bulb. 

Previous threads on this subject gave a bulb brand and part number that I found that worked on Airhead models (1979, 1981 & 1988 R100 models) with and without the multi-color circuit board (the most physically limiting factor concerning "fit") in the rear of the headlamp shell. Please do a search of the forum.

I will add that if ultimate brightness (in the 3000 lumen range) is important, then know that these brighter versions (greater than ~2500 lumens) will, of necessity, have a small fan unit on the rear of the bulb. This fan, of course, adds to the total cost of the bulb. These seem to fall into the $30-$50 range.

IMHO it is also possible to get a nice, bright LED H4 around 2000 lumens that does not have the fan, but provides very good frontal safety for on-coming drivers for daytime-only riding. The absence of the fan contributes to a more "moderately priced" bulb. I recently bought one of these on Amazon for $18.

Still an H4 LED bulb, to be effective on ANY motorcycle, should display the 3-sided column construction.

@wobbly As always, thanks heaps for the awesome education and information!