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Need advice for electric screw up on 78r100rs
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pauls1150
MOA #24991, south of Los Angeles
Did you turn on the key, or actually try to start the bike? I'd expect damage to the diode board, possibly to the regulator, possibly to the starter relay... Troubleshooting info on Snowbum's pages, https://bmwmotorcycletech.info/index.html and https://bmwmotorcycletech.info/technical-articles-list.htm
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appreciate the input so will expand. Many years ago did the "tractor battery" operation to save $. The loved and faithful bike deserved better so welded and painted the b-case and put in an expensive battery. Eye sight not being great and terminals reversed - violated the rule + If it ain't broke --. No sparks, started right up and runs great except could see voltage gage clicking back and forth so turned it off and found my mistake and corrected the cables . With key off + Red bright generator light on and parking light stays on. Basically in any position some improper lights are on. I assume the incorrect routing of electricity is the diode board is trashed. Also recognize that the voltage regulator and generator could be damaged.
Have had problems back when, 100$ cars, 6 volt voltage systems were all I could afford. Went through replacing and rebuilding generators and V. regulators. Covid and a family reunion in Estes park knocked me out of 2 reunions, aiming for Redmond?
Have had problems back when, 100$ cars, 6 volt voltage systems were all I could afford. Went through replacing and rebuilding generators and V. regulators. Covid and a family reunion in Estes park knocked me out of 2 reunions, aiming for Redmond?
stevenrankin
Well-known member
Sorry to read about it.
So you say in any position the charge light is on, the parking lights and other lights?
First question, did you see any smoke anywhere when you made the mistake? Rule out burned wires best you can. Then, for the quickest fix, I am guessing the starter relay may be flubbed up.
On the + Positive side you have one large gauge connection going to the starter motor, from there, zilch no where else. At the same time, you have another smaller gauge wire going to the under the tank starter relay. This is the first spot energy from the battery gets split up to supply ignition and power to lights and such. Usually a failure there means no start because the stater solenoid is not energized but, if something internal got damaged, who knows what else a bad relay could cause.
Starter relays are cheap, EME if they ship like the do to me can have one to you in a couple of days.
So if you see no burned out spots, oh I forgot, remove the headlight and look at the main distribution circuit board for burning/melting as well, pop in a relay and see what you got.
If after you pop in a new relay, the lights all go back to normal and the bike is running and the charge light stays on past 1500 RPM, you can bypass the voltage regulator by bridging the blue and black wires at the terminal block. If the light goes out, the v reg is bad. If the light stays on, the alternator system needs further inspection. At that scenario, a dead diode board would be possible.
Do I make sense, anyone else think I make sense? LOL, Good luck and I am hoping you didn't fry too much. On a positive note, EME may have any wire harnesses in stock. If you did melt wires and don't feel up to rewiring free hand, their replacement harnesses are pretty good, properly color coded and with the right terminals. It beats the heck out of trying to find proper gauge/color wire and good terminals to patch up a harness. St.
So you say in any position the charge light is on, the parking lights and other lights?
First question, did you see any smoke anywhere when you made the mistake? Rule out burned wires best you can. Then, for the quickest fix, I am guessing the starter relay may be flubbed up.
On the + Positive side you have one large gauge connection going to the starter motor, from there, zilch no where else. At the same time, you have another smaller gauge wire going to the under the tank starter relay. This is the first spot energy from the battery gets split up to supply ignition and power to lights and such. Usually a failure there means no start because the stater solenoid is not energized but, if something internal got damaged, who knows what else a bad relay could cause.
Starter relays are cheap, EME if they ship like the do to me can have one to you in a couple of days.
So if you see no burned out spots, oh I forgot, remove the headlight and look at the main distribution circuit board for burning/melting as well, pop in a relay and see what you got.
If after you pop in a new relay, the lights all go back to normal and the bike is running and the charge light stays on past 1500 RPM, you can bypass the voltage regulator by bridging the blue and black wires at the terminal block. If the light goes out, the v reg is bad. If the light stays on, the alternator system needs further inspection. At that scenario, a dead diode board would be possible.
Do I make sense, anyone else think I make sense? LOL, Good luck and I am hoping you didn't fry too much. On a positive note, EME may have any wire harnesses in stock. If you did melt wires and don't feel up to rewiring free hand, their replacement harnesses are pretty good, properly color coded and with the right terminals. It beats the heck out of trying to find proper gauge/color wire and good terminals to patch up a harness. St.
stevenrankin
Well-known member
How is your skill with a multi meter? Not to be a jerk but can you do continuity tests, and the like? LOL, I ask because some folk struggle.
If you have a wiring schematic on hand, you can also pop the starter relay out of its terminal and test points between terminals and such. Same for other parts of the electrical system. It also works to determine if a wire melted inside a harness and is shorting with another.
Doing any kind of electrical troubleshooting or work really needs a good schematic on hand. I personally love the ones EME sells, they are in full color, with all pins in terminal blocks and relays numbered.
Again not to make any kind of insult but when doing a continuity test of an item in place, you have to be sure the circuit you are testing is isolated from one side of the probe contact to the other. LOL, simple on some things but other things have back door paths for the current to flow and can give confusing or erroneous results. With a schematic, you can spot these in the diagram, and sometimes unplug a connection to ensure a proper test.
Not sure where you are at but if near Rochester NY, I could pop over and help or I know an airhead shop nearby. Good hunting, St.
If you have a wiring schematic on hand, you can also pop the starter relay out of its terminal and test points between terminals and such. Same for other parts of the electrical system. It also works to determine if a wire melted inside a harness and is shorting with another.
Doing any kind of electrical troubleshooting or work really needs a good schematic on hand. I personally love the ones EME sells, they are in full color, with all pins in terminal blocks and relays numbered.
Again not to make any kind of insult but when doing a continuity test of an item in place, you have to be sure the circuit you are testing is isolated from one side of the probe contact to the other. LOL, simple on some things but other things have back door paths for the current to flow and can give confusing or erroneous results. With a schematic, you can spot these in the diagram, and sometimes unplug a connection to ensure a proper test.
Not sure where you are at but if near Rochester NY, I could pop over and help or I know an airhead shop nearby. Good hunting, St.
