Introduction & Alternator Question

[mathias]

Learned Friends,

I'm new to this forum, and I'd like to introduce myself. It may be that this post should be split up or moved to the tech section; my apologies if I'm not doing it right. Please let me know.

I am very happy to have found this forum. I'm old enough to remember life before the internet, but I have no idea how we managed. I don't think I'd have bought my Spree without the knowledge that lots of information -- and helpful people -- were available on the net. Thanks a bunch to those who put all the technical information out.

I'd been toying with the idea of getting a moped for quite a while ... not so much for transportation but for cheap fun and to do the "shuttle" when going canoeing. So when I saw an ad for a 1986 Spree in "great condition" on Craigslist, and google told me it was 3 blocks north of my house, of course I went for a look-see.

Well, the "great condition" Spree didn't actually, you know, "run," and the seller wasn't too sure he wanted to, you know, "sell" --- but in the end, we made a deal whereby I fixed his '86 Spree by cleaning the carb and unsticking the float; and once it ran OK, he sold me the '85 he had in the corner of the garage for $150. Deal!

That red beauty came with 2,100 miles on the clock, two flat tires, a dead battery, somewhat banged-up body parts, and of course it didn't run either... but the engine was free, and once i pumped the tires up with my bicycle pump, I could push the silly thing home. I emptied the float bowl, cleaned the plug, measured compression while I was at it -- 155 lbs -- and had it running in a good half hour. Next, I unstuck the throttle cable and bought a new battery, and I thought I had it made. I rode it around for a few miles -- ye olde Italian tuneup -- and now fires up in 2 seconds from dead cold. Yay. Except...

I still have a couple electrical issues: Neither the headlight nor the charging circuit work.

What's puzzling is this: On the first ride, right when I got her running and I was still on the old battery, I did have high and low beam. Except the light would sometimes go off completely when I switched between the two, so I figured the dimmer switch was flaky. I don't know for sure about the charging circuit, but it must have worked, since I had working turn signals once I was up to speed, even with the bad battery. Nothing, of course, with the charger off.

As soon as I installed the new battery, no more headlight.

And no charging either: battery is 12.8 V without load; 12.3 V with the brake light / tail light on, and 11.95 Volt when running ... it looks to me that the charging circuit does not work.

I did the required tests per the manual; pp. 14-6 and 14-7:
4P Connector; yellow to engine ground is 0.8 Ohm -- Spec. is 0.3 to 2.0 Ohm.
White to engine ground is 1.3 Ohm -- Spec is 0.5 to 3.0 Ohm.

When measured from the yellow and white wire connectors coming from the alternator, the numbers are the same. Here's a picture of that wiring; I dunno if it's all stock. A previous owner may have done some futzing with the electrics, I don't know.
https://www.msu.edu/~steine13/toeff01.jpg

For reference, I measured ground to ground to see what "0" would come out to, and got numbers from 0.1 Ohm to 0.6 Ohm, depending on where I put the test points and how hard I pushed. From those measurements, I'd say regulator/rectifier and charging/lamp coil check out. But that doesn't change the fact it doesn't work...

I also looked for loose wires, but the only thing I could find that was wrong was the 7A fuse that should be on the red wire coming from the battery was missing and the wires were twisted together and taped. I used a clip lead to bridge that.
https://www.msu.edu/~steine13/toeff03.jpg
I don't see how that could be the issue.

Finally, I don't understand the sealed-beam headlight. If it's really sealed beam, shouldn't there be a plug on the back? That doesn't look like a plug to me; it's a solid connection:
https://www.msu.edu/~steine13/toeff02.jpg
https://www.msu.edu/~steine13/toeff02b.jpg

The reason I care about *that* is that i'm thinking I could easily run the headlight off 12 V DC, same as the taillight, but then I'd have to be sure that I'm not tying the stator AC circuit to 12 V; I believe that danger has been pointed out elsewhere. If I could remove the bulb from the circuit, I could make sure that that doesn't happen.

I took off the dimmer switch and measured the AC voltage coming into it (yellow wire) with the engine running.. yes, there is AC, but only ~ 1.2 V. not the 13-15 V it should be.

Does anybody have an idea what that might mean?

This post got a little longer than I intended. Any help, suggestions, further measurements I could do.... would be appreciated. Thanks in advance!

Cheers,
-Mathias

Mathias Steiner
East Lansing, MI
steine13@msu.edu

[mousewheels]

Welcome! Great work fixing the seller's Spree and getting your running.

Your electrical troubleshooting looks good, and measurements are well done.

I took off the dimmer switch and measured the AC voltage coming into it (yellow wire) with the engine running.. yes, there is AC, but only ~ 1.2 V. not the 13-15 V it should be.

Does anybody have an idea what that might mean?

Try unplugging the regulator and repeating the measurement on the Yellow stator wire. Some failures of the regulator have been found to drag down the headlight output. Also, measure the AC voltage on the stator 'white' wire before and after unplugging the regulator. Two cautions: It sounds like your stator output is very heavilly loaded with the engine running. Stator could be damaged should it be ridden that way for long. Next - if unplugging the regulator restores headlight output, riding at high speeds may blow or reduce the life of the headlamp and other bulbs on that circuit. You'd want to replace that regulator soon.

Going backwards to lesser issues:
The fuse holder being missing often points out the previous owner had some electrical problems. Repeated blown fuses often lead some to bypass the fuse. One common reason we've found for blown fuses is a bad regulator. It's wise to get a fuse back into the circuit sometime in the future. If the battery (or jump starting) is connected in reverse polarity, it can lead to melting wires if no fuse is present.

Here's some past topics related to charge system failures
http://www.hondaspree.net/phpBB3/viewto ... tor#p61320
http://www.hondaspree.net/phpBB3/viewto ... =regulator

[mathias]

Mousewheels,

Thanks a lot for your helpful post.

Try unplugging the regulator and repeating the measurement on the Yellow stator wire. Some failures of the regulator have been found to drag down the headlight output. Also, measure the AC voltage on the stator 'white' wire before and after unplugging the regulator.

I measured AC voltage at both yellow [light] and white [charging] alternator wires.

(1) Regulator CONNECTED, yellow & white alternator wires unplugged
[EDIT: Table format seemed like a good idea but doesn't work too well with this font. Ugh.]

cranking running [something like a fast idle]
-------------------------------------------
Yellow 3 V 20 V
White 5 V ~38 V

(1 b) As above, but white wire connected:

cranking running
-------------------------------------------
Yellow 0.5 V 1.3 V

(2) Regulator DISCONNECTED, yellow & white wires unplugged.

cranking running
-------------------------------------------
Yellow 3 V 20 V
White 5 V 30 V

All voltages in these measurements appeared to increase linearly with engine RPM. That's just a guess, since I don't have a tach.

Also, I didn't test the yellow output under a load... I don't want to blow the headlight by running 20 V where 12 should be... I think I'll do it just very briefly as the engine catches, that should be safe. First I have to put the dimmer switch etc. back together.

[EDIT: Yes, light comes on w/ regulator unplugged.]

So I believe I'm in luck and all I need is a new regulator. Yes?

Where do I get one? A quick look on ebay shows a bunch of used ones between $10 and $20 and some new ones from $40. I guess I could just get it from the local Honda dealer and not worry about waiting and shipping... what do you suggest?

Thanks again for your help. Without it, my only option would be to blindly replace parts.

Cheers,
-Mathias

[mousewheels]

<< complete set of measurements - good work >>

So I believe I'm in luck and all I need is a new regulator. Yes?

Where do I get one? A quick look on ebay shows a bunch of used ones between $10 and $20 and some new ones from $40. I guess I could just get it from the local Honda dealer and not worry about waiting and shipping... what do you suggest?

Yes, you got it - bad regulator. Used has worked for me, but few seller's test it thoroughly like you just did. Sometimes there are full harnesses sold with electrical parts still connected. It can be handy to have a spare of everything on hand - or a second scooter

[mathias]

Thanks to a valued forum member and the good offices of the USPS, I got a used regulator/rectifier in the mail today.

I can say definitely that things have improved. Whether all is well I'm not so sure.

First step: Install and connect regulator. Start bike. Huzzah! Scooter runs, headlight works.

Now, the measurements, and here I'd be grateful for advice again:

Measuring across the battery, + post vs. - post, it's 11.8 V with the scoot running and the regulator disconnected. With the new regulator connected and the engine revved, it's 12.3 V at maybe 5,000 rpm. Don't have a tach, but half of 'all out' is about right. The wife was around at the time, so full throttle was contraindicated.

Lamp circuit, measured straight from alternator, with everything connected and the engine revved, climbs as high as 16 V (AC). This is much lower than before -- it was 20 V @ maybe 3,000 rpm -- so I'm guessing that's OK.

The white wire that goes towards the charging circuit, again taken with everything else connected, goes up to 30 V AC, which is pretty much what it did before.

Questions:

1) Isn't the 12.3 V charging voltage a little low? Shouldn't it be 14 V or thereabouts? And if it isn't right, who is the likely culprit? It's clear that the new regulator does something right, as it raises the voltage across the terminals by 0.5 V; is there something else the matter? This was with the head light, tail light, and brake light on and the engine running, so I'd expect some current draw / voltage drop.

2) Is 16V safe for the headlight?

I should mention I used a good Fluke meter, so the numbers ought to be good.

What say the experts?
Thanks in advance,
-Mathias

[mousewheels]

First step: Install and connect regulator. Start bike. Huzzah! Scooter runs, headlight works.
--> Yay!

With the new regulator connected and the engine revved, it's 12.3 V at maybe 5,000 rpm.
--> Thats low. But just off a start and idling the battery could be drawing the max current the regulator will source. If you ride a few minutes and repeat the 5k test, does the battery voltage get higher?

Is 16V safe for the headlight?
--> Sounds high, In a bench test, the regulator did a good job dumping energy as needed to regulate around 12.8vAC. http://www.hondaspree.net/phpBB3/viewto ... uit#p97158

[Lunytune]

I am very happy to have found this forum. I'm old enough to remember life before the internet, but I have no idea how we managed.

I'm old enough to remember life before computers and wrote my theses on a manual Royal typewriter. Don't know how I did it.

This thread is of interest to me. I don't have charging problems at this time, but have had bulb problems and suspect over voltage, so I'm reading with interest. Keep it up. Mouse is a good teacher, just takes time to hammer into a thick skull.

[mathias]

Mousewheels,

Thanks for the reply. I figured the best way forward is to get yet another regulator and see if that'll simply fix everything.. in the meantime, I just don't ride a lot...

With the new regulator connected and the engine revved, it's 12.3 V at maybe 5,000 rpm.
--> Thats low. But just off a start and idling the battery could be drawing the max current the regulator will source. If you ride a few minutes and repeat the 5k test, does the battery voltage get higher?

I did that. Waddayaknow, when I came back from my little 2-mile ride, the voltage across the terminals was 12.4 at idle and rose up to 14.5 V when revved. Alrighty then!

I didn't feel like taking the engine cover off to get to the headlight wiring, so I'll do some more tests when regulator #3 gets here.

Thanks again for your help,
-Mathias

[Lunytune]

when I came back from my little 2-mile ride, the voltage across the terminals was 12.4 at idle and rose up to 14.5 V when revved.

A perfect battery should measure 13.2 plus with key off. 12.4 at idle would suggest lights are pulling more than alternator can keep up with, which is expected. Don't worry about that. 14.5 v when revved up would be normal. All of this part sounds OK to me.

[mousewheels]

Waddayaknow, when I came back from my little 2-mile ride, the voltage across the terminals was 12.4 at idle and rose up to 14.5 V when revved. Alrighty then!

Great - charger side sounds to be doing its job

I've been wondering about the scope waveforms shown in the prior links. There were some large peaks, which mightconfound some meters. Today, took out an old school VOM and the Fluke true RMS meter. For the stator output of the '86 Gyro, the two meters tracked well. Idle was around 9.5v with a dim light, full throttle around 12.8 VAC.

Photo shows reading of about 11v. It is at much less than full throttle - maybe 1/3 or so... Hard to juggle the throttle, balance the bike and take a pic

[mathias]

I didn't feel like taking the engine cover off to get to the headlight wiring, so I'll do some more tests when regulator #3 gets here.

Sorry for the delay, guys.

At any rate, I got alternator #3, and it performs exactly like #2.. so I'm assuming both are OK.

Voltage across the battery is fine, as mentioned above. My concern was the headlight, where the voltage climbed past 15 V as the revs went up.

This time, I spliced in a thin wire into the yellow connector and measured the voltage under load. Even at ~ full throttle, I only got 14.6 V, which I'm going to pronounce "safe" for the headlight.

It's still higher than the 12.8 V that mouse measured on the bench, but I'll be ignoring that ;->

Next job: Figure out how to transport the Spree using the trailer hitch on my Pontiac Vibe. If I come up with something clever -- I may have to -- I'll let y'all know.

Thanks again for the help!

Cheers,
-Mathias