Donald's Antique Rototillers Motorcyle Page

Revised 5 September, 2009

105-amp Alternator for the GL1000

  When I purchased my 1978 Honda Goldwing GL1000 K3 the bike had a bad alternator stator that I didn't know about. I hooked up a solar panel to the cigar lighter to charge the battery while I was not riding even while I was out and about.

  I put up with this for a little while until my desire to make longer rides, I'm talking about 100 miles at that time. Since the stator is inside the rear cover of the engine, I had to pull the engine, quit a job the first time.

  I added driving lights but the 18-amp alternator could not handle the load. I replaced the 55-watt lamps with 35-watts lamps, the alternator would maintain about 12.3 vdc with them on. LED lamps would reduce the electrical load of the front and rear marker lights about half but they are relatively expensive so I never went that route. I later added heated grips and I have a Widder vest with arm chaps. I can't run the extra lights and heated gear at the same time.

  While researching a replacement stator I came across a website by Donald J Pigott, "Instructions for Installing GM Alternator on GL1200", I later came across Donald (PoorBoy) on Classic Wing SIG. PoorBoy in replies to others about bad alternators mentioned he sold kits. Finally after I had enough riding in poor lights and being cold I decided to buy a kit from him.
*** Classic Wing SIG link is not good any more so Google Classic Wing SIG ***

After the 1st of January, 2006 the weather was looking bad for a few weeks so I started installing the kit and alternator that I already had. The first step is to remove the radiator and expose the timing belt covers.

The kit came with a 12mm bolt, spacer, and metric pulley. It turns out the GL1000 uses a 10mm x 1.25 bolt on the forward end of the crankshaft to retain the timing belt pullies.
*** Also this bolt kept spinning on me so I had a machinist pin the pulley, spacer and timing belt pulley together. Also I would use a V-belt pulley instead of the multigrove micro belt pulley that came with the kit. ***

I ordered two 12mm to 10mm x 12mm bushings and a 10mm x 1.25 x 50mm metric bolt from McMaster-Carr. I used Saf-T-Lok R01 Fast Retainer to glue the bushings in. I had to file the bushings down, I should had ordered them with 10mm length.

I mounted the timing covers on a 2x4 and drilled a 1-3/8" hole. The pilot drill walked a bit and the hole is about a 1/8" lower then I wanted it but it stills cleared the pully and spacer.

Here is the right timing cover back in place. While I had it apart I replaced the two timing belt idler springs with new factory ones, I had makeshifts springs in there. I also retensioned the belts. I had a repaired gooseneck at the thermostat so I installed the good used one I purchased from Frenchy on the ClassicWing SIG. The black angle and spacer is part of PoorBoy's kit, it's the lower alternator bracket but I don't use it since I mounted the alternator on the right side.

Two spacers, about 1/2" thick comes with the kit to push the lower part of the radiator forward to clear the pully. The GL1000 or at least mine has two 6mm bolts that attach the radiator at the bottom, no studs like the top. I took two 40mm length bolts, cut the heads off and using threadlocker I made studs to attach the spacers.

The weather got warm so I put the radiator back on so I could ride and just finish up the project later. The kit shows the alternator on the left side but once I installed the radiator I realized there was no way a serpentine belt was going to clear the fan shroud. The instruction showed removing one of the fan bracket legs but the GL1000 is different. So I decided to put it on the right side.

The lower bracket was too short for use on my GL1000 so using it as a sample I made a longer one with a adjustment slot. The serpentine belt does not come with the kit. For my setup I need a minimun of 34 inch belt, 3 ribs. It turns out Gates Micro-V belt comes in 34 then 65 inch is the next length. The 34, Gates/CarQuest part number K030334, is very tight. Gates makes a K040335 which is a 4-rib belt and 35-inch, I am going to buy one of these, cut the extra rib off and put it in my onboard spares.

The upper bracket is the kit lower bracket, filed to clear the frame tube and the adjustable bracket I had from something else. I would like to get this whole setup remade for appearance later. The upper bracket that came with the kit was designed to attach to the fairing on a GL1200, I knew when I purchased the kit I would have to make a different one. The right horn has to be relocated, that's for another day.

The original alternator I was going to use turned out to be only 37-amps. I traded it for a new 105-amp unit. I routed a 10-gauge wire from the alternator to the battery. I am running a Deka AGM battery already because servicing the water in a regular battery was a pain. To run a 105-amp alternator you need a maintenance free battery AGM or GEL cell or you will cook it dry. I would like the alternator up higher but it would prevent me from opening the right side cover to check the coolant.

  Now for the test. I disconnected the stator from the rectifier to see what the new alternator would do. The alternator doesn't kick in until about 1700 rpm's but then 13.9 vdc. I reinstalled the two 55-watt lamps in the driving lights. With the driving lights on, high beams on, my GL1000 is wired so the low beam stays on with the high beams on, and heated grips on high the voltage drops to 13.5 vdc at 2000 rpm's. But at a stop the voltages drops low, below 12 vdc, motorcycle batteries don't have much reserve to play with. I have a 5-function digital gauge that beeps when voltage gets below 11.5 vdc so I get beeped. If need be I just thrown on the throttle lock and set it so the alternator kicks in. My battery is 1-1/2 years old and has been abused alot so a fresh battery may stay closer to the 12 vdc range at idle. I'm happy with the results, I am looking for more power while on the go, I can always turn things off when I'm stop.

  Next project: Audiovox Cruise Control...Never got it to work Right

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After the 1st of January, 2006 the weather was looking bad for a few weeks so I started installing the kit and alternator that I already had. The first step is to remove the radiator and expose the timing belt covers.
	The kit came with a 12mm bolt, spacer, and metric pulley. It turns out the GL1000 uses a 10mm x 1.25 bolt on the forward end of the crankshaft to retain the timing belt pullies. * Also this bolt kept spinning on me so I had a machinist pin the pulley, spacer and timing belt pulley together. Also I would use a V-belt pulley instead of the multigrove micro belt pulley that came with the kit. *
I ordered two 12mm to 10mm x 12mm bushings and a 10mm x 1.25 x 50mm metric bolt from McMaster-Carr. I used Saf-T-Lok R01 Fast Retainer to glue the bushings in. I had to file the bushings down, I should had ordered them with 10mm length.
	I mounted the timing covers on a 2x4 and drilled a 1-3/8" hole. The pilot drill walked a bit and the hole is about a 1/8" lower then I wanted it but it stills cleared the pully and spacer.
Here is the right timing cover back in place. While I had it apart I replaced the two timing belt idler springs with new factory ones, I had makeshifts springs in there. I also retensioned the belts. I had a repaired gooseneck at the thermostat so I installed the good used one I purchased from Frenchy on the ClassicWing SIG. The black angle and spacer is part of PoorBoy's kit, it's the lower alternator bracket but I don't use it since I mounted the alternator on the right side.
	Two spacers, about 1/2" thick comes with the kit to push the lower part of the radiator forward to clear the pully. The GL1000 or at least mine has two 6mm bolts that attach the radiator at the bottom, no studs like the top. I took two 40mm length bolts, cut the heads off and using threadlocker I made studs to attach the spacers.
The weather got warm so I put the radiator back on so I could ride and just finish up the project later. The kit shows the alternator on the left side but once I installed the radiator I realized there was no way a serpentine belt was going to clear the fan shroud. The instruction showed removing one of the fan bracket legs but the GL1000 is different. So I decided to put it on the right side.
	The lower bracket was too short for use on my GL1000 so using it as a sample I made a longer one with a adjustment slot. The serpentine belt does not come with the kit. For my setup I need a minimun of 34 inch belt, 3 ribs. It turns out Gates Micro-V belt comes in 34 then 65 inch is the next length. The 34, Gates/CarQuest part number K030334, is very tight. Gates makes a K040335 which is a 4-rib belt and 35-inch, I am going to buy one of these, cut the extra rib off and put it in my onboard spares.
The upper bracket is the kit lower bracket, filed to clear the frame tube and the adjustable bracket I had from something else. I would like to get this whole setup remade for appearance later. The upper bracket that came with the kit was designed to attach to the fairing on a GL1200, I knew when I purchased the kit I would have to make a different one. The right horn has to be relocated, that's for another day.
	The original alternator I was going to use turned out to be only 37-amps. I traded it for a new 105-amp unit. I routed a 10-gauge wire from the alternator to the battery. I am running a Deka AGM battery already because servicing the water in a regular battery was a pain. To run a 105-amp alternator you need a maintenance free battery AGM or GEL cell or you will cook it dry. I would like the alternator up higher but it would prevent me from opening the right side cover to check the coolant.