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Discussion Starter · #1 ·
Honest. I'm not being lazy. So as not to waste your time I have already scoured the forums for a solid half-hour in search of the answers to my questions, but can't find exactly what I'm looking for.

Simply put, my battery isn't charging. I've done everything I can think of to track down the problem (see list below if you're interested), which has finally lead me to the stator/generator/alternator/coil. On a side note, does anybody know the difference between a stator/generator/alternator/coil? My group of riders has always used them interchangeably.

I digress. Here are my questions. '71 CL450.

1. What is the specification range for resistance for the three wires leading from my stator? With my limited knowledge on the subject, I've heard that anything falling between 0.1 and 2.0 is fine, but have been unable to secure a definitive answer. Is this true? I've checked the three wires in pairs A-B, B-C, and A-C. Their readings are 0.6, 1.2, and 1.4 ohms.

2. Assuming that these readings fall into the proper specs, do they all need to be at approximately the same reading? Or is it okay that they vary so widely from 0.6 to 1.4 ohms?

Thank you for your help.

Just in case, here are the diagnostics I've already completed without any positive results.

- Checked all the connections and leads that have anything to do with the charging system. All are clean, connected, and fine.
- Tested for a parasitic draw. No problems.
- Load tested the battery both at home and at O'Reilly's. It's fine.
- Checked the rectifier diodes. Fine.
- Shouted obscenities.
- Couldn't figure out how to test the regulator, and because the output on these old bikes is pretty anemic, I went ahead and installed a reg/rec combo. I bought it from a reputable knowledgeable Honda Twins source, and I am confident that I installed it properly.
- After the reg/rec installation, the battery continues to slowly lose voltage on its center-stand while tested at 5,000 - 6,000 RPM's.
- Which now leads me to the dreaded stator.

Any ideas? Thanks!
 

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The stator readings will differ. One pair of wires goes to two coils in parallel, from power to common, so the reading will be the lowest - this is the pair that is connected when the headlamp switch is on. Another pair will be the single coil, from power to common, and will be higher - this is the coil that operates all the time. The third pair reads through the first and second combined, power to common to power, so adds the previous two. Reading such low values is difficult for most common meters, which is why you see readings that don't exactly add up. Still, your numbers sound about right, for most common meters.

At idle, around 1000-1100 rpm, the single stator coil will just keep even with the load, so if you measure the battery Voltage, it should set just about 12.6-12.8V. Raise the rpm to about 3000, and it should go up, indicating it is charging the battery; how high depends on how discharged the battery is, but when the battery reaches full charge, it should be about 14.2V. When you turn the lights on, it will slowly discharge the battery at idle, and reaches break-even closer to 1500rpm. Full charge rate would be somewhat above 3000rpm.
Text Diagram Line Circle Parallel
Note that there is no dot at the center, so there is no connection there.
 

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Stop throwing parts at it.
Download the FSM.
recheck wiring for RR.
Before you started changing parts, you should have checked the voltage at the battery with bike idling (12VDC), then at 3000 rpm (13.8VDC). if not good, check for voltage going into the regulator (on a stock setup) should vary with engine speed. If not good, check AC voltage going into the rectifier.
How it should work (my numbers might not be accurate); Alternator output varies around 30-70VAC depending on RPM's and goes to the rectifier where it is converted to 15-18VDC where it goes to the regulator where it is regulated to an output of 12-14VDC then goes to the battery and the rest of the bike.

IIRC, at 3000 RPM there should be about 70VAC coming out of the stator.

There are quite a few threads on what exact ohm readings the stator should have.

This is for the Kohler RR but should work for you.
Plan Text Floor plan Line Diagram
 

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You should also measure resistance from any of the wires to the case - it should read open.
 

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Discussion Starter · #5 ·
Thanks, Rick. Yeah, I'm just using a Craftsman meter, so it'll have to make due. I've got a similar diagram to the one you've posted in my manual, and they even list some equations to go along with it. I can fully understand the diagram, but navigating the equation eludes me. Your explanation is helpful.

As far as RPM's, doesn't seem to matter. While idling at 1100 RPM's, the voltage slowly drops with no increase in the charge. Same at break even RPM's, same voltage drop. Even as high as 6,000 RPM's there is no gain in battery voltage, just the same slop drop. I hadn't considered taking into account whether the headlight is on or off, but I wouldn't think that would really matter when I'm running at 3-6K RPM's, am I right?

Thanks for the reminder about checking for the stator grounding out. I actually had already done that, but forgot to list it. I'll keep plugging along and figure it out sooner or later. But not 'til next week. Good ol' Mom's visiting from out of town, so I've got other priorities for the next few days. Thanks again.

Larry
 

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Discussion Starter · #6 · (Edited)
Hi Jim,

"Stop throwing parts at it" is always sound advice, and I wholeheartedly agree. Here-here! But I wanted to update the reg/rec anyway, so figured this was the perfect opportunity.

I've already got a bound FSM that I work from, so we're squared away there.

Admittedly, I'm tired of checking and rechecking for resistance in the wiring, but will likely do it yet again five times more just to make sure. Just the way I am.

The battery voltage drops at a trickle whether I'm at 1,100 RPM idle speed or 3K RPM break even. Same thing at 5K RPM. There's nothing coming into the battery.

This bike has only ever had a separate reg and rec, so since I've recently installed the new reg/rec I'm not exactly sure how to check the voltage going into it. Any ideas? Can the combo reg/recs even be tested? What wires are doing what and what voltage is going where and how does it combine on the inside somewhere, etc. I don't know. But I'll consult the manual and verify which wires are going where, but not until the weekend (Mom's visiting from out of town, so she's the priority this week). I'm sure that if I sit and think about it, I can probably figure this part out.

Why I haven't thought to check the voltage coming directly out of the stator, I don't know. Good idea. So what, just back probe it at the connector?

Thanks for the info and the attachment. I'll check them out. I appreciate your time.

Larry
 

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For the record the 450 DOHC has a permanent magnet alternator. This is a primitive design that that puts out a fixed amount of current. The bike's electrical system must be balanced against the output of the alternator. Back when the bike was new Honda rated the total amount of output at 110 watts. The ignition system needs around 50 watts and the reset if left for the lights and to charge the battery. To make up for the difference between lights on and lights off, the alternator has two modes of operation; day time (lights off) and night time (lights on). With lights on the entire bike's electrical system uses around 85 watts and and what is left over charges the battery. If there is too much current left over the battery will boil off the electrolyte. If there is not enough then the battery goes flat.

1. What are the battery voltages at the battery? Please post them with the engine off, the engine at idle with the headlight off, the engine at idle with the headlight on, the engine at 3500 RPM with the headlight off and on. there should be five readings.
2. What ignition are you running? Stock points or electronic, stock coils or lower Ohms (high energy spark) coils.
3. What wattage headlight are you running? Stock headlight for 1971 is a 30/35 Watt sealed beam.
4. What rectifier are you running? In '72 Honda changed the rectifier from Selenium based diodes to Silicone based diodes.

Changes to the lighting and ignition systems will effect the performance charging system. Additionally there has been progress in the design of rectifier/regulators. If you look through the part specs, Honda changed the headlight from 30/35 to a 50 watt high beam (i don't recall the low beam wattage) in '72.

If you are not seeing a short or an open circuit is the stator coils, it would be safe to assume it is OK. Next thing to look at is the wiring through the handlebar switch. The alternator's white and pink wires are connected together. This puts the alternator in night time mode so the alternator puts out full voltage. That is why I'm asking for the readings with the headlight on and off. It is possible the magnets in the alternator have lost some strength. Let me know what you find.
 

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The pink and yellow wire going into your RR are the AC voltages coming off the alternator. The red/white is the regulated DC output to the bike and battery..
 

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Discussion Starter · #9 ·
Thank you, Jim and Jim. Lots of great info that I will soon apply. But I won't get back out into the Wrench Cave until next week. Talk to you then. I appreciate all your help.
 

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Honestly it is more than likely that your stock rectifier and regulator are no longer able to charge the bike properly. They were never that good when new :)
Converting them over to a modern all in one RR unit like the Kohler or Sparckmoto is a no brainer and will only improve the bike's over all charging capability.

http://www.hondatwins.net/forums/50.../14014-cheap-regulator-rectifier-upgrade.html


This was one of the best mods I ever did on my bike.
 

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Honestly it is more than likely that your stock rectifier and regulator are no longer able to charge the bike properly. They were never that good when new :)
Converting them over to a modern all in one RR unit like the Kohler or Sparckmoto is a no brainer and will only improve the bike's over all charging capability.

http://www.hondatwins.net/forums/50.../14014-cheap-regulator-rectifier-upgrade.html


This was one of the best mods I ever did on my bike.
he has already changed to a RR combo.
 

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Discussion Starter · #12 ·
I'm in full agreement, 76TWIN, but I already replaced them for all the reasons you've mentioned. Good idea, though.
 

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You say you installed a reg/rec combo - got a link? Also, did you remove the stock regulator? It works by shorting the stator, and if it still connected and has gone bad, could be the problem.
 

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Discussion Starter · #14 ·
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