More charging problems

Joined
May 17, 2015
Messages
16
Location
Santee, CA
Bike
ST1100
Hi folks.
I recently purchased a 1995 1100 with 148,000 miles. It had a water leak, when I tore it apart one of the water fittings on the heads was corroded through. I replaced both fittings and all hoses. No more leaks. The thing rides great and I love it, BUT now I have a charging problem. The regulator is charging over 15 volts and gets so hot after 2-3 minutes I can't touch it. On a ride it quits working after about 10 minutes. I checked the alternator wiring and it checks good according to the book. The regulator has VERY low resistance between the red/'white and the white wire, supposed to be 60 ohms.
I purchased a new RR and installed it. Now I get NO charging and this regulator has no contiuity between the red/white and white wire terminals.
The RR I got was one of those from china, at $25, delivered.

My question is, is there anyone that changed to the 40 amp system that has a known good RR that they would be willing to sell me?
 

wjbertrand

Ventura Highway
Joined
Feb 8, 2005
Messages
4,407
Location
Ventura, CA
You can't really test the OEM regulator without the specific meter shown in the service manual. Using a different meter, no matter how high quality, gives erroneous results. When you checked the alternator wiring, did you check all three important parameters? 1. continuity should be present between any combination of the three phases of the alternator. 2. there should be no continuity to ground of any of the three. Lastly what is the out put of each phase with the engine running? Should be I think around 30 volts/phase.

Historically it is the alternator that's more the trouble point than the regulator, discounting the tendency for overheated and burned connectors. Can't speak for the Chinese regulator, didn't know there was an option for that.
 
Joined
Mar 13, 2012
Messages
5,046
Location
soCal
Bike
'97 ST1100
STOC #
687
Hi Herb,

Don't know how much voltage tracing you've already done, but one reason your regulator could be putting out 15V is corrosion induced voltage drops in your main electrical path. Haven't had to trace it out on the ST, so I don't have a wire-by-wire procedure to share, but basically it goes like this.

System voltage at battery goes to main ignition switch. On the other side of the switch somewhere there will be a point where the regulator senses the voltage drop across the switch. Based on that voltage drop it determines how much electrical load is on the system, and adjusts its output accordingly. If one or more connectors in that path have corrosion or otherwise compromised connections that increase the voltage drop between the battery and the other side of the switch where the regulator is sensing voltage, your alternator/regulator output will be higher than normal voltage across the battery.

I'd put the original regulator back in and see what the voltage drops look like. If they look OK, then your regulator may be the problem, but if you find some excessive drops you may be able to fix those and keep using the original regulator. I'd expect the normal drop to be in the range of 0.7-1.0V or so. If you have significantly higher drop than that, then trace the path starting at the battery and try to find where the excess drops are located and fix them.
 
OP
OP
Joined
May 17, 2015
Messages
16
Location
Santee, CA
Bike
ST1100
In answer to both posts.
The alt wiring checks with no problems, according to the honda manual.
continuity between all yellow wires, black and white wires are the correct ohms and no shorts to ground. The terminals are all in good shape.
The original RR reads low resistance on the red/white to the white terminal. The new RR reads no continuity between the 2 and the rest of it reads good.
What I do know is that the original RR is putting out WAY more than it is supposed to and the new one is putting out nothing.
I have switched them out 5 times and it is always the same.
If it were a corrosion problem both regulators should react the same. Since I have different problems when switching the regulators, it really does appear that it is a RR problem.
The red/white wire is battery voltage all the time. The black wire is ignition voltage. I get battery voltage on both of them, there is less than .5 volt drop between the battery and the black wire and no drop on the red/white wire.
I didn't check the no load voltage on the yellow wires, the honda manual doesn't give a test for that. No idea what it should be.
 
Joined
Mar 13, 2012
Messages
5,046
Location
soCal
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'97 ST1100
STOC #
687
OK, good to know. I wouldn't put too much faith in the $25 Chinese regulator, so you may now have two bad regulators instead of just one.
 
OP
OP
Joined
May 17, 2015
Messages
16
Location
Santee, CA
Bike
ST1100
Pretty much the conclusion I came to.
Since I bought it on EBay, with pay pal, I sent a message to the supplier.

Meanwhile... I was hoping someone had done the 40amp upgrade and would have the RR left over. More than willing to purchase it.
 

kiltman

Site Supporter
Joined
Apr 27, 2013
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68
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Stratford, Ontario Canada
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2002,ST1100ABS
STOC #
8826
My system puts out between 14.7- 14.9 I had it up to 15.1 but I changed the battery and it sits at 14.8 all the time. I would eliminate the red connector from the three yellow wires from the alternator and solder them directly.
I would expect to see some melting of connectors at the main relay and the VRR. I have to ask, did you actually remove them to inspect? or did you do a visual inspection whilst they were still connected. If they are still in good shape check the internals of the connectors, you may need to do a little crimping to ensure a tight connection.
 
OP
OP
Joined
May 17, 2015
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Location
Santee, CA
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ST1100
I pulled them apart. The book calls for the tests to be done from the 2 and 3 pin connectors. Both are perfectly clean and bright.
The battery is new and reading 12.8vdc.
I also ran the test from the RR connector. Same readings except for the black and white wire. The black wire provides power to all of the ignition system. if reading with the 2 pin connector hooked up, I get a ground when reading the white or black wires to ground.
 
Joined
Feb 28, 2015
Messages
5
Location
New Zealand
More Charging Problems on my ST1100
I went on a weekend ride last weekend and got about 150km from home and the bike died. The battery had run low on charge so out in the country and nobody stopped to help had to ring family for a trailer ride home. After recharging battery and doing the alternator and battery checks found low voltage coming to the battery so cleaned all the plugs and battery terminals, hay presto voltage back to 14.4 volts but a wiff of smoke from under the seat. Next day went to start up the ST and it started then blew the 10 amp ignition fuse so tried again and it blew again. Can anyone give me some ideas please.

Davo NZ
 
Joined
Feb 2, 2009
Messages
2,304
Location
Dahlonega, GA
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2018 NC750X
STOC #
7666
More Charging Problems on my ST1100
I went on a weekend ride last weekend and got about 150km from home and the bike died. The battery had run low on charge so out in the country and nobody stopped to help had to ring family for a trailer ride home. After recharging battery and doing the alternator and battery checks found low voltage coming to the battery so cleaned all the plugs and battery terminals, hay presto voltage back to 14.4 volts but a wiff of smoke from under the seat. Next day went to start up the ST and it started then blew the 10 amp ignition fuse so tried again and it blew again. Can anyone give me some ideas please.

Davo NZ
You most likely have a short in the harness. Check for a short between ground and the offending circuit. Check for chaffed wiring anywhere it hugs the frame.
 
Joined
Feb 28, 2015
Messages
5
Location
New Zealand
You most likely have a short in the harness. Check for a short between ground and the offending circuit. Check for chaffed wiring anywhere it hugs the frame.
Thanks for the quick reply Vinny, will give that a go in the morning.
Cheers
Davo nz
 
Joined
Nov 20, 2015
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20
Location
Kent WA
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04' ST1300A
STOC #
8890
Thought I could add my two cents here. While troubleshooting my charging issue I learned a couple of things. The dynamic AC test was very helpful across the yellow terminals in the VR/R. So while the bike is running above 3000 rpm check that the AC voltage output is correct from the Alternator to the VR/R. Meter across each phase to the other. If you have to unbolt the VR/R to do this make sure you put a ground from the VR/R Case to the bike frame as it needs this ground in order to work as there is no ground in the harness. Does this make sense?
 
Joined
Jun 3, 2006
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3,512
Location
British Columbia
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2021 RE Meteor 350
You can disconnect the red 3P connector and check the three coil outputs from the alternator side of that connector. I would disconnect first, then start the engine and do the AC volt measurements. They should all be within a few volts of each other, somewhere around 25VAC. The black/white 2P connector must be connected.

If your multimeter has a diode tester, you can also check the diodes in the VRR. I found I had one bad diode in there when I was having problems on my '95 several years ago.
 
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