Intermittent Electrical Problem 77XS650

thuban

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I'll try to keep this short and to the point so people can follow. 77 XS stock with exception of LED Head lite, Harness mod to turn off HL warning lite, Starter Soleniod wire unplugged and Flasher unit replace with 2 prong. (Starts on first or second kick when cold and first kick when warm. I hate the "possum in a shitcan" sound when you hit the starter and metal in the oil, so...)

Volt meter says charging system working well. Fuel mix is light brown on the plugs. Good steady idle, even down to 800 when warm. Timing chain adjusted and timing dead on. No burbling or pops on throttle off coast downs and instant pick ups on throttle roll.
Down the road we go. Running great. Suddenly it starts banging out and jerking, both jugs are missing, not a steady miss on just one. Running good again. Hummmm, water in gas? Cross-road-demonds? Back at home and a couple of hours, checked everything. Nothing. Starts great, seems to run good. I have had it break up a bit before but never been able to get my head around it. Most of the time it's flawless.

Few days later, down the road we go. About 15 miles out and same thing. She gets me back home but jerking has loosened/stretched the chain. It was terrible but I didn't want to push it! Adjusted that. I'm thinking fire to the coils. I pulled the tank. The bullet connectors are loose in their plug-ins. I clean and slightly crimp each one, to the coils and points. ( time has taken it's toll on the connectors. They have lost their spring and won't stay snug.) I zip tie them to the frame so they won't flop around.
Down the road we go. A 50 mile round robin and it don't get any better. Am I good or what?!

{{ Warning: You don't have to read thru all the BS below....Just skip to the third paragraph from the bottom to "Continue Reading." Thanks. }}

Few days later, down the road we go, about 12 miles and I pull into the feed store. ( All my old friends sitting on chairs, like ducks in a row, spitting and lying! I do the mess-around trying to get the "green" light... finally! I reach for the key and before I got my hand half way there, engine shuts off. ( It sure got quite and there all looking at me) I put in on the stand, took my helmet off, questioned their heritage and went inside.
I chewed the fat for a bit and decided to take my leave. I goes out, straps into my helmet and turns the key on. I check the head light, yep, brake lites, turn signals, green neutral, seems to have good power, good to go. (Theres four of em'. They ain't said shit but there looking. ) Turn on the gas, and kicks it over. Nothing, just like a cold priming kick. I'm staring at the green neutral lite. Three more careful kicks and the forth kick it spits like a startled cat. ( "Well, the POS is shiny!" Haw, Haw, Haw...) Ok, I heard that!

( Fats in the fire now. I know it didn't jump time.) I drag out the tool kit, off with the head lite to rattle wires, you know the drill. Nothing. Everythings working but it doesn't seem to be getting any fire. ( They got me surrounded - shuffling their feet... " I got some duck tape in the truck." - " I got some baling wire!") I'm really feeling low. I gets it back together. The trouble-shooting team, closely assembled, is not the one I would have picked! I carefully kicks it a few times with meaning. I must have been rolling the throttle some when I kicked it. It ROARED to life and the team took some steps back! ( Now that's funny!) I hollered, "Look out!" "Your fixing to get your sorry asses run over!"

I pushed her back, dropped it in first ...and it died! - " Haw, Haw, Haw...." " You shuda rode that damn Honda...HawHawHaw... " - I thought, thank god my tinted visor is down, they can't see me cry! I got the green light. First kick and were outa there! All the way home, perfect. Down shifts, turns and stops, I kept about 2K PRMs under it a bit. I got a shot of whiskey while it was cooling off. I started it a couple of times and it fired right up. Snake bit!

Continue reading:

I'm still thinking it's a power problem to the coils. ( I'm using a XS650D wiring schematic so... )Lets see, power comes off batt, thru the 20 amp fuse ( which I had up-graded - soldered-in modern flat holder and 20A fuse) with a lead off to rectifier and on to the IGN SW. From the IGN SW a brown wire runs to the Engine Stop switch ( with a lead off to the Instrument lights, which worked so I know I was getting power thru the IGN switch) From the Engine Stop switch, a Red with White to the Safety Relay (that I have disconnected from the Starter Sol.) But on the way to the Safety Relay the Red with white goes straight to power both coils, and I already went over those and zip tied them to the frame) Hummmm I'm laying in the hospital thinking, a day or so before the terrible feed store ride, the throttle had been binding a bit. I pulled the thottle and controls off the bars to lube the cable. I'm thinking the Engine Stop switch does not ground out the coils when you switch it, or it would blow the fuse. There can't be an intermittent short to ground in the wire from the IGN switch feeding the safety relay and coils, or again, it would blow the fuse. It has to be an intermittent in the Engine Stop switch! The Stop Switch must work by only opening the circuit to the coils. It feels normal each way but it would explain all the times the bike breaks up on rides. ... I'm not really able to mess with it yet.

I think what I will do, after I am able to work on the bike and check the Stop Switch, is make up a fused wire with a clip on one end for the batt positive and the appropriate end on the other, so if this happens again, I can dissconnect the Red with white wire in front of the coils and plug the coils directly to the batt positive. That should allow the engine to run isolated from everything else in the electrical system. I hate to have the bike start breaking up and start flipping the stop switch to see what happens.
Any bets? Suggestions? Ideas? Something I've overlooked?
Thanks,
Thu
 
Do the "relay mod" where coils receive +12VDC directly from the battery, via a 10 amp fuse and a standard automotive ("Bosch") relay. Then use the original +12VDC with the convoluted path you just described, to acticate the relay. Only extra wiring needed is the one from battery to relay. And a very short wire from the relay coil to ground. Just search for "relay mod" here on the forum.

Btw, i like Ry Cooder's music :)
 
I have been in your boat and wish you good luck. I have replaced coils, fixed wires, plugs, carbs, even a new battery was faulty. The one thing that gave me the most head ache was the fuel cap seal not venting and I thought it was everything else. My advice keep your cool and try one thing at a time.
 
I'm in the systematic battery to coils electrical R&R. Since it's intermittent you can't just "look for the problem" you go through every connection and component making sure it's up to snuff and working properly. full R&R of ignition and kill switches, must do's. Just normal life with old stuff.
PS loved the feed mill tale. can see the porch and line of cronies!
 
I have been in your boat and wish you good luck. I have replaced coils, fixed wires, plugs, carbs, even a new battery was faulty. The one thing that gave me the most head ache was the fuel cap seal not venting and I thought it was everything else. My advice keep your cool and try one thing at a time.

Yep, Bushy, the fuel cap vent got me too but was a quick find because everything else was a complete frame up rebuild. I have 745 miles on the bike since rebuild. I should have replaced the wiring harness. :doh: To be honest, I did disassemble all the controls and switches, cleaned and lubed. I did not mess with the Stop switch. I don't use it. I use the key. I think of the stop switch as a emergency switch and hope I never have to use it. Thanks for the reply. Much appreciated. Thu
 
Go through that stop switch! Never opened one that didn't need it.
It's kind of misnamed, think of it as a GO switch, all the coil current has to go through it, easy for water to get in there, corrode things.
 
I'm in the systematic battery to coils electrical R&R. Since it's intermittent you can't just "look for the problem" you go through every connection and component making sure it's up to snuff and working properly. full R&R of ignition and kill switches, must do's. Just normal life with old stuff.
PS loved the feed mill tale. can see the porch and line of cronies!
Yep, gggGary, It's ego deflating, I tell ya. Yes, It is possible there is a broken wire in a loom also, like the 90 degree bend in front of the tank up to the light bucket. I think that would be rare since I ohmed everything out on build. It's really gona be a head scratcher if the Stop switch isn't intermittent. Thanks gggGary.
 
Go through that stop switch! Never opened one that didn't need it.
It's kind of misnamed, think of it as a GO switch, all the coil current has to go through it, easy for water to get in there, corrode things.
Exactly my thinking. That's where my trouble shooting took me. I'll try to get into that switch soon and take a look.
 
Do the "relay mod" where coils receive +12VDC directly from the battery, via a 10 amp fuse and a standard automotive ("Bosch") relay. Then use the original +12VDC with the convoluted path you just described, to acticate the relay. Only extra wiring needed is the one from battery to relay. And a very short wire from the relay coil to ground. Just search for "relay mod" here on the forum.

Btw, i like Ry Cooder's music :)

I'm thinking about this solution. If I wired it up using the Red w/white from the Stop switch to the actuation prong of the relay, I would still have the problem, if it's the stop switch. Plus I have added more items to the system to troubleshoot in the future. BUT, If I ran the Red w/white wire BEFORE the stop switch, removing it from the equation, then I would/should have a hot power source directly from the batt to relay to coils with the Ign switch only powering the latch relay.
I like it! I could also jumper around the Stop switch and go straight to the coils. Source would be directly to the coils, with exception of Safety realy, but not as "Hot". Hummmmm. Good Idea! Thanks much, Arctic!
 
Actually, the best solution is to clean up all connections, switches and relays in the original current path, and fix any intermittent open circuits in the wiring. And then install a relay, to ensure the voltage drop between battery and coils are kept to an absolute minimum. A 10 % voltage drop actually gives 19% less power (wattage) And since oem XS coils are pretty marginal to begin with, you don't want to compromize them even further.
 
Actually, the best solution is to clean up all connections, switches and relays in the original current path, and fix any intermittent open circuits in the wiring. And then install a relay, to ensure the voltage drop between battery and coils are kept to an absolute minimum. A 10 % voltage drop actually gives 19% less power (wattage) And since oem XS coils are pretty marginal to begin with, you don't want to compromize them even further.
Yep, I've had my hands, ohm meter and soldering iron on everything but that stop switch. How many people actually use the stop switch to kill the engine before turning off the key switch. They teach it that way in the riding school but I don't use it.
 
How many people actually use the stop switch to kill the engine before turning off the key switch. They teach it that way in the riding school but I don't use it.
It's part of my "daily check." First ride of the day.... turn the key on, kill sw to kill (both sides) and hit the starter. Eng should not start. Kill sw to run, start the bike. While it warms up check the horn, lights..... usual suspects for looseness....
Other than that I don't use it either, but I suspect that daily drill helps keep the contacts clean.
 
Another thing. I think after I get this problem taken care of, I want to replace the regulator and rectifier with solid state. By my volt meter on the bike, my charging system is working perfectly. (if it ain't broke...) But like Mark Twain said, He didn't care for a man that could spell a word only one way. Been a while, but I have read thru the regulator and rectifier mods and I've slept since then and have CRS. I read there are many units that work, or not. Like the LED head lite mods with Resistors that get hot, and remote ones and mounting restrictions...WOOF. I like the KISS method. Like my Optronics LED head lite, No ballast resistors, it does not get hot and almost a direct replacement for that sealed beam, but it's expensive. So what will work best on my stockish 77? I'll have to sift thru the info again. I have some N144 diodes 1/2 watt if memory serves, and heat sinks around here some place but I don't want to make a rectifier. Much easier to follow in someones knowledgeable footsteps and bolt on something that's commonly available and works well. Lucky duck, I do have a brand new regulator and rectifier if needed but...
 
It's part of my "daily check." First ride of the day.... turn the key on, kill sw to kill (both sides) and hit the starter. Eng should not start. Kill sw to run, start the bike. While it warms up check the horn, lights..... usual suspects for looseness....
Other than that I don't use it either, but I suspect that daily drill helps keep the contacts clean.

Hummm, I'll bet that's right , Jim. I do check the lights, especially since XS has the on/off switch. Honda HL is on all time, no switch. Cold and damp today and bike is covered up. I'm itching to check the stop switch but it's the first day I can go the head with out the burn. It's a whisky day. Heres to ya! :)
 
I do have a used ignition coil off my 80 xs650G, but I am not 100% if that is for digital ignition only. If that is something you might want to get off me just shoot me a PM. I upgraded to an andrews coil myself when I was chasing my electrical problem that ended up being my brand new battery. Since I replaced the AGM with a lithium battery I haven't had anymore electrical problems.
 
I do have a used ignition coil off my 80 xs650G, but I am not 100% if that is for digital ignition only. If that is something you might want to get off me just shoot me a PM. I upgraded to an andrews coil myself when I was chasing my electrical problem that ended up being my brand new battery. Since I replaced the AGM with a lithium battery I haven't had anymore electrical problems.

I'll keep that in mind , Bushy. I have a new coil that came with my HHB system that is un-installed. I figured what the hell... I went out and tore into the stop switch. More on that in a bit. ( I just happen to have a 1980 engine, just in case, that has TCI? Right now it's a conversation piece and will require a "black box" or other to make run.)
 
Ok, I couldn't stand it. Had to check the Stop Switch. Looks good so far.
1 look.jpg


Probably why I never messed with it. but on we go. I takes it apart and it looks nasty. I had never worked the switch till I thought about it being the problem.
2 switch.jpg

See the little crack up above. Screws are kind of corroded too. Crack goes all the way around to the front of the contacts.
3 crack.jpg

So,, I repaired the crack with Pro CA cyanoacrylate and hit it with kicker. A bit blurry but crack is healed.
4 crack fix.jpg


Hummm. whiskey class is empty too, I see. I got it all back together. Hasn't run in two weeks. It's 57 damp degrees. Turn on the gas, put on the choke. Kick it one time and turn on the key. One more time and it starts on the first kick....That's my baby! 30 seconds or so and it starts to load up and run rich, flip off the choke and she idles about 1100 rpm.
5 running.jpg


LED head Light on low beam. charging 13.1 V. I love it. I gas it just a little and it sits at 13.1. Don't want to gas it much and blow a hole in my sump filter.
Boys, it don't get any better than this. I think that's a fix. We'll see on Wednesday when it's clear and 81 degrees.
 
I'd start looking for a new Rt switch assembly. That crack will start again. Probably somewhere else. Plastic get old and brittle then cracks. I've never found just the switch.
 
I'd start looking for a new Rt switch assembly. That crack will start again. Probably somewhere else. Plastic get old and brittle then cracks. I've never found just the switch.

I haven't either. I have already repaired the light switch solders. They just break off with vibration. I can see the backing starting to bow from the force of the springs. Thanks, Azman
 
Ok, I couldn't stand it. Had to check the Stop Switch. Looks good so far.
View attachment 162432

Probably why I never messed with it. but on we go. I takes it apart and it looks nasty. I had never worked the switch till I thought about it being the problem.
View attachment 162433
See the little crack up above. Screws are kind of corroded too. Crack goes all the way around to the front of the contacts.
View attachment 162434
So,, I repaired the crack with Pro CA cyanoacrylate and hit it with kicker. A bit blurry but crack is healed.
View attachment 162439

Hummm. whiskey class is empty too, I see. I got it all back together. Hasn't run in two weeks. It's 57 damp degrees. Turn on the gas, put on the choke. Kick it one time and turn on the key. One more time and it starts on the first kick....That's my baby! 30 seconds or so and it starts to load up and run rich, flip off the choke and she idles about 1100 rpm.
View attachment 162438

LED head Light on low beam. charging 13.1 V. I love it. I gas it just a little and it sits at 13.1. Don't want to gas it much and blow a hole in my sump filter.
Boys, it don't get any better than this. I think that's a fix. We'll see on Wednesday when it's clear and 81 degrees.

Might be time to head back over to the feed store and show those rockin chair cowboys how well your bike starts now!
Hey by the way, got any close ups of your little voltmeter and how you’ve got it mounted? I like it.
 
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