125m electrical issues...is this common?

[Daddio]

I have a super clean 84 125m that has been driving me nuts with electrical problems.
The biggest problem to date is that it won't charge the battery. Some times it will run with the key off and sometimes it wont. It shouldn't need to have the key on to run. The lights, starter and everything else work great.
I have a factory service manual....and I've tested the alternator and the voltage regulator. They both test good. I even bought another voltage regulator and it didn't change anything.
I was thinking about picking up a used wiring harness but every one I've seen looks like junk.
Is this model known to have electrical issues or does mine just have them all? :wondering

[DasUberKraut]

Sounds like a crossed wire?

[Daddio]

I don't really think it has a crossed wire. I did notice that in the process of checking things out it started running with the key on or off, which is how it should be. But after a little more messing around it went back to running with the key on, only. I'm thinking maybe a bad connector or wire, but I'll be damned if I can figure out which one.

Here are a few pics. I know, pics or STFU.

http://i39.photobucket.com/albums/e183/lrdunlap/Picture006.jpg (http://s39.photobucket.com/user/lrdunlap/media/Picture006.jpg.html)

http://i39.photobucket.com/albums/e183/lrdunlap/Picture005.jpg (http://s39.photobucket.com/user/lrdunlap/media/Picture005.jpg.html)

http://i39.photobucket.com/albums/e183/lrdunlap/Picture007.jpg (http://s39.photobucket.com/user/lrdunlap/media/Picture007.jpg.html)

[kb0nly]

Actually it should NOT run with the key off. If it did then whats the point of a key?? LOL

I have dealt with a few 125M's, can't say they all had electrical gremlins though.

I would eliminate the keyswitch first, unplug the Green and Black wires and then plug together the Yellow and Yellow/Red wires. This will keep the ignition on and the power to the lightswitch. So the lights should turn on and off with the light switch.

Check the 7a fuse under the seat. If the fuse is good then put a voltmeter on the battery, see what the voltage is without the engine running and lights off, then start it and see if the voltage goes up, even at idle you should see it climb up to near 13v, if you rev it you should see the voltage go up with the rpms. If it doesn't then there is no output from the regulator/rectifier to the battery. The 7a fuse is between the output of the regulator and the battery, remove the fuse and check the voltage on the regulator/rectifier end of the fuse holder to make sure there is input to the fuse, and then remove the other end from the starter relay and put the fuse holder back together and check to make sure you have voltage at the ring terminal that went on the relay. I have replace a lot of those glass fuse holders due to corrosion with a newer ATC (funny the auto fuse is an ATC, no pun intended) style auto fuse.

Also check that relay terminal and the ring terminals as the battery cable is on the same terminal, clean them, check to make sure they aren't loose, etc. The other regulator/rectifier you tried was it known good tested on another trike?

Sounds like your ignition switch is bad for one! The contacts go bad in them and you get that run/no run issue.

[DasUberKraut]

It's true that 30 year old wiring can be problem filled. Especially corrosion.

I wanted to create my own harness for my 125m.

[kb0nly]

Oh another suggestion... On the 85 i was working on the engine/frame end of the negative battery cable was intermittent causing low battery voltage and not charging. I unbolted it and cleaned it and then no more charging problem on that one.

The 125m harness wouldn't be too hard to create honestly, its not too many wires between the points of the wiring.

[DasUberKraut]

I work for a cable and wire company too. I just need to match the correct style of wire and I bet they'd give me a few spools out of the scrap hoard.

Also, nice clean 125m Daddio. That needs the 185s/200s front end conversion! :beer

[Daddio]

Actually it should NOT run with the key off. If it did then whats the point of a key?? LOL

I have dealt with a few 125M's, can't say they all had electrical gremlins though.

I would eliminate the keyswitch first, unplug the Green and Black wires and then plug together the Yellow and Yellow/Red wires. This will keep the ignition on and the power to the lightswitch. So the lights should turn on and off with the light switch.

Check the 7a fuse under the seat. If the fuse is good then put a voltmeter on the battery, see what the voltage is without the engine running and lights off, then start it and see if the voltage goes up, even at idle you should see it climb up to near 13v, if you rev it you should see the voltage go up with the rpms. If it doesn't then there is no output from the regulator/rectifier to the battery. The 7a fuse is between the output of the regulator and the battery, remove the fuse and check the voltage on the regulator/rectifier end of the fuse holder to make sure there is input to the fuse, and then remove the other end from the starter relay and put the fuse holder back together and check to make sure you have voltage at the ring terminal that went on the relay. I have replace a lot of those glass fuse holders due to corrosion with a newer ATC (funny the auto fuse is an ATC, no pun intended) style auto fuse.

Also check that relay terminal and the ring terminals as the battery cable is on the same terminal, clean them, check to make sure they aren't loose, etc. The other regulator/rectifier you tried was it known good tested on another trike?

Sounds like your ignition switch is bad for one! The contacts go bad in them and you get that run/no run issue.

I've checked all of those things and the only time the voltage changes is when I turn on the lights, then it drops. I unplugged the alternator and checked it, per the manual, and it checked out good. The only other thing I can think of doing is unplugging and checking the alternator while it's running. I'm not sure what the output should be but I guess if it is making voltage, I will be even more suspect of the wiring. The worst part of this machine is the main harness runs through the body and it looks like I'll need to pull the engine out to completely remove the harness.

[barnett468]

Hello


Is your regulator NEW or used?

Is it an original or unknown [probably Chinese] unit?



I've checked all of those things and the only time the voltage changes is when I turn on the lights, then it drops.

It may drop at idle but is it more or less at 2000 rpm than with the lights off?

Is it more, less or the same at 2000 rpm with the lights off as it is idle?





I unplugged the alternator and checked it, per the manual, and it checked out good.

I would check it both hot and cold just because. I would also to see of there is continuity between both the leads and the engine. It’s a dumb test but if there is then it is grounded and therefore bad but it shouldn’t be.





The only other thing I can think of doing is unplugging and checking the alternator while it's running. I'm not sure what the output should be but I guess if it is making voltage.

Good idea, I think it should be a minimum of 25-50 volts at around 2000rpm, obviously anything over that is a bonus. It should be less at idle. Unplug it at stator not the regulator for this test. One test lead goes to one of the stator wires the other test lead goes to the other stator wire.






I will be even more suspect of the wiring.

This is easy. You can use 2 safety pins for any connectors you can’t easily probe, just stick them into the wire so you can connect the volt meter test lead to them.

1. Check continuity from the back side of the voltage regulator plug on the stator side to the matching wire on the regulator side. Do this with the ALL the wires. If one has no continuity the connection is likely just dirty. Clean connection until continuity is achieved then test for proper charging again. If it still doesn’t charge proceed to next step.

2. If the alt has decent voltage when unplugged then unplug the stator at the stator and unplug the regulator then check both yellow stator wires for continuity from end to end and from end to engine or chassis. If there is continuity from end to engine or frame there is obviously a short and you can track it down or bypass the old wire with a new one then retest for proper charging. If there is no problem or it still doesn’t charge after the repair then proceed to next step.

3. With the regulator unplugged and all switches off and key switch unplugged [because it is bad] check continuity from black wire with red stripe from alt plug to aluminum battery post, not the bolt or wire connector on end of wire. If there is no continuity then remove fuse and check continuity from alt plug to end at fuse then end at fuse to aluminum post on battery then end of wire to bolt on battery. Fix as necessary and check charging again.

If you do all this and it still doesn’t charge then you most likely have one of two problems.

a. DIRTY CONNECTION – Believe it or not a wire can test good across a connector using continuity and voltage but still be dirty enough that it won’t carry sufficient amperage/current across the connector. I have seen and fixed this exact problem many, many times.

b. BAD REGULATOR – Even though it is new it is likely bad irregardless of how it tests.

[Daddio]

Thanks, barnett for all of the effort you put into this. I have two other running machines that just need some checking over and general maintenance that I'm going to focus on this weekend so I'll have at least two ready for TF. I'm going out of town next weekend and so that doesn't leave much time to get stuff ready especially if this thing keeps eating up all of my time. I'll post back up what I find when I finally figure it out. hammer :beer


Hello


Is your regulator NEW or used?

Is it an original or unknown [probably Chinese] unit?




It may drop at idle but is it more or less at 2000 rpm than with the lights off?

Is it more, less or the same at 2000 rpm with the lights off as it is idle?






I would check it both hot and cold just because. I would also to see of there is continuity between both the leads and the engine. It’s a dumb test but if there is then it is grounded and therefore bad but it shouldn’t be.






Good idea, I think it should be a minimum of 25-50 volts at around 2000rpm, obviously anything over that is a bonus. It should be less at idle. Unplug it at stator not the regulator for this test. One test lead goes to one of the stator wires the other test lead goes to the other stator wire.







This is easy. You can use 2 safety pins for any connectors you can’t easily probe, just stick them into the wire so you can connect the volt meter test lead to them.

1. Check continuity from the back side of the voltage regulator plug on the stator side to the matching wire on the regulator side. Do this with the ALL the wires. If one has no continuity the connection is likely just dirty. Clean connection until continuity is achieved then test for proper charging again. If it still doesn’t charge proceed to next step.

2. If the alt has decent voltage when unplugged then unplug the stator at the stator and unplug the regulator then check both yellow stator wires for continuity from end to end and from end to engine or chassis. If there is continuity from end to engine or frame there is obviously a short and you can track it down or bypass the old wire with a new one then retest for proper charging. If there is no problem or it still doesn’t charge after the repair then proceed to next step.

3. With the regulator unplugged and all switches off and key switch unplugged [because it is bad] check continuity from black wire with red stripe from alt plug to aluminum battery post, not the bolt or wire connector on end of wire. If there is no continuity then remove fuse and check continuity from alt plug to end at fuse then end at fuse to aluminum post on battery then end of wire to bolt on battery. Fix as necessary and check charging again.

If you do all this and it still doesn’t charge then you most likely have one of two problems.

a. DIRTY CONNECTION – Believe it or not a wire can test good across a connector using continuity and voltage but still be dirty enough that it won’t carry sufficient amperage/current across the connector. I have seen and fixed this exact problem many, many times.

b. BAD REGULATOR – Even though it is new it is likely bad irregardless of how it tests.

[kb0nly]

If the voltage drops when the lights are on then its either the alternator/stator coil or the rectifier/regulator, only two things it can be at that point, been there done that!

If you unplug the alternator output and put a voltmeter across the yellow wires, with the meter set to AC, you should see anywhere from 20-30 volts depending on engine speed. At idle the 125M i was working on had about 19v but its idle was also set a little low at first i never measured it after adjusting that.

When you turn on the lights your adding a load to the regulator, so as long as the alternator output is good it will only sag if the regulator is bad and doesn't compensate for the load on it. Thats what happened on my 200ES as well when the regulator/rectifier went this year, the battery wouldn't hold a charge and the lights would work but i could see the system voltage drop when on. Replaced it and everything was good to go again.

[Daddio]

I was on a roll yesterday with the trikes, so I decided to try something with this one. After checking the wiring diagram again, I unplugged the wire that goes from the fuse to the ignition switch. The voltage regulator also feeds into this circuit, so I unplugged it also. Then I hooked a 6volt battery to the switch end of the wire via a jumper wire and checked the voltage at the fuse end and the regulator end. There was no voltage to the regulator end so my guess is that where they are spliced together, somewhere in the body, the connection is bad. I spliced it into the fuse wire and it charges now. It's not charging as high as it should though. I tried the other regulator and it was exactly the same reading. My guess is that the alternator is a little weak. I ordered another one from ebay, just in case. The reading at the battery at idle is 12.74 volts. Off idle it is 12.95 to 13.07.

[barnett468]

Hello Daddio



it charges now. It's not charging as high as it should though. I tried the other regulator and it was exactly the same reading. The reading at the battery at idle is 12.74 volts. Off idle it is 12.95 to 13.07.

If this is the voltage with the system connected then in my experience doing this many times your charging voltage is exactly what it should read with your battery so high. You have a 12V battery that reads 12.75 volts which is .75 volts high so the regulator see’s this and say’s the battery is not hungry so I don’t need to feed it therefore it doesn’t send much voltage to it.

If this is the voltage output from your stator when it is disconnected then the stator is bad.

If you turn your light on with the engine off for 15 minutes and then check the battery voltage and charging voltage the battery might read 11.5 and the regulator might send it around 14 volts slowly decreasing in charging voltage as the battery voltage increases. If you turn the light on while it is running and check it at idle and at 2000 rpm it should read over 13 volts at 2000 rpm.





My guess is that the alternator is a little weak.

I see nothing yet that suggests your stator is weak.




What is the voltage output from your stator with it unplugged?

[barnett468]

Forgot to mention, glad you got it fixed.

[dougspcs]

I was on a roll yesterday with the trikes, so I decided to try something with this one. After checking the wiring diagram again, I unplugged the wire that goes from the fuse to the ignition switch. The voltage regulator also feeds into this circuit, so I unplugged it also. Then I hooked a 6volt battery to the switch end of the wire via a jumper wire and checked the voltage at the fuse end and the regulator end. There was no voltage to the regulator end so my guess is that where they are spliced together, somewhere in the body, the connection is bad. I spliced it into the fuse wire and it charges now. It's not charging as high as it should though. I tried the other regulator and it was exactly the same reading. My guess is that the alternator is a little weak. I ordered another one from ebay, just in case. The reading at the battery at idle is 12.74 volts. Off idle it is 12.95 to 13.07.

Did this also fix the key off issue?

[Daddio]

Forgot to mention, glad you got it fixed.

I'm glad too. Thanks!!! :D
I never did check the output directly from the stator.

[Daddio]

Did this also fix the key off issue?

Everything works properly now. I think the key off issue was corrosion on one of the connectors. I went through and cleaned them all and put dielectric grease on them all. I figured that I better do that to eliminate a faulty connection as the cause of my charging issue. I'm glad I finally got the gremlins worked out of it. Now I can ride it!!!:w00t: :beer

[kb0nly]

12.74 at idle isn't that bad. A fully charged battery is around 12.6v roughly, so if its at 12.7 at idle the battery is fully charged or nearly full, as the engine rpm increases the voltage increases as well, but that doesn't mean the battery needs to be at that voltage, the voltage just rises with the regulator cutting off around 13.8v.

Sounds like you got it working!