Going with diy poorboy

I did some research and found a commercially available pulley that was recommended for the crank. It is a 3-rib microgroove pulley with a bore diameter of 0.670" or 17.08mm. Come spring I will probably order one and try it on the project bike in question, but it may be a trial-and-error sort of thing, or at worst it may be the sort of thing where we start with it and modify it slightly to work. The pulley comes with a mounting bushing to also fit on a 15mm shaft.

The items I found that are thought to work are all available from KRC Power Steering and are as follows in the list below.

PLEASE NOTE: I HAVE NOT TRIED ANY OF THESE PARTS AS YET BUT FOUND THEM LISTED ON OTHER WEBSITES. I DO NOT KNOW FOR CERTAIN ABOUT THEIR SUITABILITY BUT WILL POST MORE NEXT SPRING AS I GET INTO MY PROJECT AND LEARN MORE.
If someone else wishes to try them out before I have the opportunity or can share more information, it would be very helpful. It would be very nice to be able to put together a thread that contains all of the part numbers for parts that can be purchased and drawings for the parts that need to be made plus a wiring diagram along with a set of instructions to follow to complete the project, eliminating the need for individuals to hunt down the answers they need individually over and over again. Granted, this is information that may not be needed frequently enough for anyone to offer a commercially available kit, but having it available for the DIY guys would be an advantage.

Alternator, either of the following (or there are others available) I believe these are both self-exciting and have internal regulators:
A. Denso 12V 85A Heavy Duty Alternator, KRC part no. POW8182 $340.18 Part # POW 8182 - Alternators - Alternators and Accessories
B. Denso 12V 50A Sportsman Alternator, KRC part no. POW8172 $236.47 Part # POW 8172 - Alternators - Alternators and Accessories


Alternator Pulley: 1.75" Denso Alternator Pulley, KRC part no. KRC 40130340 $31.99 Part # KRC 40130340 - Alternator Pulleys - Alternators and Accessories


Crank Pulley: 2.5" Denso or Delco Alternator Pulley, KRC part no. KRC 40140300 $43.99 Part # KRC 40140300 - Alternator Pulleys - Alternators and Accessories

A one wire alternator system only needs the connection to the battery but may require the engine to be revved up slightly before the alternator begins to produce current. One way around this is to use a two-wire setup instead where the lead from the battery connects to the battery lead on the alternator and there is a second wire from the ignition switch that supplies current to the regulator and tells the alternator to start charging. Which one will work best on the Goldwing I do not know, but myself I would try to go with the two-wire setup.

That is all I have for now folks. If anyone has anything to share, please do!

Igetbisy said:

Keep crank pulley small diameter. Interferes with fan, and causes alternator to charge/draw at idle. Not so great.

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I don't know why I did not see this sooner. Can you be more specific about the diameter for the crank pulley? The 2.5" pulley listed for the crank is what someone listed on another website. If 2.5" is too large, it would be nice to know what size does fit properly.

As for charging at idle there are some things to consider:

• The old stator system is a full-loss system. It is charging at maximum capacity for its engine speed at all times. At idle speeds they would typically cover the "live load" of engine electrical and low-beam headlamp, but that was about all, maybe 10 amps total, 138 watts, or 0.19 HP. Not much of a load, but still a load, nonetheless. These systems produced highest wattage output at maximum engine speed. The regulators on these systems did not control power generation but instead dumped excess power to ground and by creating heat.
• Alternators on the other hand, regulate power produced by monitoring system voltage and modulating the current to the alternator field coils to keep voltage constant. As engine speed goes up, field coil current goes down. When engine speed drops, field coil current is increased to keep alternator output at a constant 13.8 VDC.
• Due to the differences in regulator function, the original stator is disconnected, and the original regulator and rectifier are removed and discarded. Since stator removal is a more difficult procedure that requires engine removal, the stator is left in place. Leaving the original stator in place but disconnected will not do any harm or impart any extra load on the engine. The alternator used in its place already has its own regulator and rectifier mounted internally.
• Some charging systems do not begin to produce current until a certain RPM is reached after engine start up. "One-wire" charging systems are very prone to that issue. However, once the RPM has been increased enough for the system to begin charging, it will continue to charge at all engine speeds, even if the engine is returned to idle. Charging never fully stops until the engine is shut off.
• Once charging has begun and the engine is at idle, the regulator will increase the field current to the alternator to increase output and keep the system at 13.8 VDC. Either way, the system will charge at idle and put a small and largely imperceivable load on the engine.
• That load is probably in the neighborhood of about 15 or 20 amps even while recharging the battery after engine startup. For the sake of this discussion, let's set the number a little high and call it 25 amps. This equates to 345 watts or a 0.46 horsepower load on the engine.
• There is a low RPM point where the alternator will not produce current even with a full field voltage of 13.8 VDC. This is undesirable because you now have a situation where you have a number of things drawing power from the battery such as the engine ignition system, headlamp and tail lamp, stereo (if it is turned on) and the alternator field coils, but with no power going back into the electrical system. Ideally you do want the system to charge somewhat at idle, at least enough to cover the current electrical system load. Battery recharge can take place once the bike is moving and the engine is operating at higher but normal speeds.
• Long story short, pulley sizes are part of a balancing act where we are trying to balance electrical generation at idle against electrical power usage at idle. In most cases, the pulley sizes selected are such that the alternator turns 1.5 to 3 or 4 times the speed of the engine. Increasing the alternator speed at idle reduces the current required for the field coils of the alternator.

My apologies for the long post, but since we are talking about alternators and electrical power generation, I felt it better to cover some of the details so that everyone reading this can have a better understanding of the subject, leading to a better discussion for everyone.

I believe I have all of the information I need to move forward with the alternator conversion on Kevin's (my wife's first cousin's husband) '84 1200 Interstate. I fully intend to document the project in detail and post it all here in its own thread so that others may benefit from step-by-step instructions for their own conversion projects. I suspect that mounting brackets will be slightly different between the 1100 and 1200 bikes, but do not yet know what those differences might be. Once the 1200 project is complete, I might decide to seek out an 1100 owner in my area that is interested in doing a conversion so that we can document any differences in pulley or belt sizes, bracketry, and steps to follow.

Sorry if I am late to reply, I have tried à few different pulley sizes in my qu'est to get one to spin true with no vibration. Here are my finding. Unless you really need alot of power for some reason. Output is of minimal importance. Things to be concerned with are thus: larger pulley interférer more with fan. They also provide à larger mechanical advantage against the bolt to loosten it as the rotation is backward for the application. If the alternator has to work really hard, the force will be pretty strong. Pulley must turn as close to absolutely true as possible. The vibration transfert to alternator and wreaks havoc everywhere. Not all bolts are the same, make sure hole in pulley matches shoulder of bolt. Some bolts have smaller diameter after threads. If possible, find a pulley with it's own shoulder to space from end of crankshaft. The longer the hole, the better. The hole is perpendicular to pulley and helps to ensure alignement. If I were to start over. I would buy a 4 or 5 inch aluminum pulley, with à deep shoulder. I'm sorry I can't give dimensions unless I take it all back apart and mesure them, but if it does come out again I will. Timing cover bolts aren't an issue because it's easier to remove pulley to access them in this configuration.

Thanks for the information based on your experience, it is helpful!

You mentioned the problem with the crank bolt being the only thing holding the pulley, and that the pulley will tend to loosen the crank bolt. Additionally there is the issue with the shoulder of the crank bolt not being a precision fit in the pulley bore, leading to vibration issues. I do have a plan to address those issues, but I also have an advantage over the average person performing this conversion: I have a small machine shop of my own and can machine a custom precision crank bolt or make other modifications to ensure that the alternator crank pulley runs true. It may also be possible to find a commercially produced shoulder bolt of proper dimensions to do the job. The standard hardware store bolt would not even be considered.

As for a positive drive of the pulley, a simple drive pin can be installed in the crank pulley, and a coinciding hole can be drilled into the crank timing pulley, which I assume is already keyed to the crankshaft.

Granted, most folks don't have access to a machine shop to make custom modifications, but getting into this project in spring will give me the opportunity to maybe come up with a different solution. We shall see when the time comes.