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techtalk:ref:elec30 [2020/02/08 17:26] hippysmack [Ironhead Wiring Mishaps and Meltdowns] |
techtalk:ref:elec30 [2020/02/09 18:28] hippysmack [The Doctor71'S 1974 xlh] |
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====== Ironhead Wiring Mishaps and Meltdowns ====== | ====== Ironhead Wiring Mishaps and Meltdowns ====== | ||
\\ | \\ | ||
+ | See also illustrated [[techtalk:ref:elec07|1959-1985 Sportster Main Wiring Diagrams (created with reference to the OEM manual)]] in the REF section of the Sportsterpedia. \\ | ||
- | It's important to have some sort of fail safe mechanism whether a fuse wire, fuse or circuit breaker inline between the battery and the voltage regulator. \\ | + | It's important to have some sort of fail safe mechanism whether a fuse wire, fuse or circuit breaker inline between the battery and the voltage regulator. ((The Doctor71 of the XLFORUM http://xlforum.net/forums/showthread.php?p=5805036#post5805036)) \\ |
- | Else you can unsuspectingly experience a experience a dead short, melted wiring or even watching your bike go up in flames (literally). \\ | + | Else you can unsuspectingly experience a dead short, melted wiring or even watching your bike go up in flames (literally). \\ |
It appears that HD's quick fix in 1974 to the meltdown was Service Bulletin #659 adding a fusable wire inline from the battery. \\ | It appears that HD's quick fix in 1974 to the meltdown was Service Bulletin #659 adding a fusable wire inline from the battery. \\ | ||
[[techtalk:ih:elec02#fuse_wire|Clich here to see more on the fuse wire]] in the Sportsterpedia. \\ | [[techtalk:ih:elec02#fuse_wire|Clich here to see more on the fuse wire]] in the Sportsterpedia. \\ | ||
+ | It's important to have some sort of protection on the main circuit. \\ | ||
+ | If it applies to your ride, you can ward off a potential meltdown in multiple ways. Do whatever works for you: | ||
+ | * By following HD Service Bulletin #659. | ||
+ | * Installing an extra circuit breaker. | ||
+ | * Installing an inline fuse. | ||
+ | * Or all of the above. | ||
+ | |||
+ | |||
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====== Broken Horn Bracket ====== | ====== Broken Horn Bracket ====== | ||
- | Horn brackets that are mounted along with the key switch between the cylinders has been known to cause meltdowns. \\ | + | The horn bracket that is mounted along with the key switch between the cylinders has been known to cause meltdowns. \\ |
- | The fact of the bracket breaking (due to being loose, vibration, age etc,) isn't the problem. \\ | + | The fact of the bracket breaking (due to being loose, vibration, age etc,) isn't the problem (electrically speaking). \\ |
The key switch terminals are bare ended (no insulation). \\ | The key switch terminals are bare ended (no insulation). \\ | ||
Should the horn bracket break, the horn will (most likely) swing down & rest on the back of the ignition switch for awhile, shorting the terminals. \\ | Should the horn bracket break, the horn will (most likely) swing down & rest on the back of the ignition switch for awhile, shorting the terminals. \\ | ||
The subsequent dead short heats up the wires, melting them and triggers the carnage shown below. \\ | The subsequent dead short heats up the wires, melting them and triggers the carnage shown below. \\ | ||
At this point, the motor is dead, no lights, no nothing. You're stranded on the side of the road, wondering just what happened. \\ | At this point, the motor is dead, no lights, no nothing. You're stranded on the side of the road, wondering just what happened. \\ | ||
+ | ===== The Doctor71's 1974 xlh ===== | ||
- | This happened to a 74 XLH all initially started by a broken horn bracket: \\ | + | This happened to my 74 XLH and all initially started by a broken horn bracket: \\ |
- | This particular bike did not come with a fuse wire installed from the factory. So the main circuit was unprotected. \\\\ | + | This particular bike did not come with a fuse wire installed from the factory. So the main circuit was unprotected. \\ |
See the 'before' pic of the horn / switch brackets below (taken ≈ 8 months prior to my catastrophic event). \\ | See the 'before' pic of the horn / switch brackets below (taken ≈ 8 months prior to my catastrophic event). \\ | ||
The ends of the ignition switch wires were heat-shrink'd immediately after this pic was taken. \\ | The ends of the ignition switch wires were heat-shrink'd immediately after this pic was taken. \\ | ||
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+ | ===== Hopper's 1977 XLCH ===== | ||
+ | |||
+ | Or: Most carb problems are electrical. ((Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021)) \\ | ||
+ | |||
+ | Hopper had been fine tuning the Keihin carburetor to get a nice reliable idle without carb farts, stalling, or unwanted high-idling. \\ | ||
+ | Riding around the back roads in the sugar cane fields near home. Coldest morning of the year (50 degrees F , perfect for breaking in a new engine). \\ | ||
+ | |||
+ | I lean out the idle mixture screw so it is idling beautiful, but then it gets a misfire in the midrange. \\ | ||
+ | I head for home. The misfire starts happening at full throttle too. Maybe some of that carb cleaner I sprayed in the idle mix screw hole has dissolved an O-ring? \\ | ||
+ | Or is sitting in a gob in the float bowl and acting like water in the fuel - I have had that happen before. \\ | ||
+ | |||
+ | So I pull into my buddy`s driveway - the aircraft engineer and BMW restorer - to see if maybe he has a 0.80mm drill I can open my intermediate jet up just a tad with. \\ | ||
+ | I let the bike sit there and idle for a good minute or more. Beautiful. Perfect in fact. \\ | ||
+ | |||
+ | I kill the engine and get off. Ferkin ell, there`s smoke coming off the battery. \\ | ||
+ | I look and see the positive wire from the battery to the regulator is glowing red hot. \\ | ||
+ | Then before my eyes, flames start licking up the battery. \\ | ||
+ | The rubber battery box mount is on fire and the flames are licking at the rubber mount above it. \\ | ||
+ | As I look for the nearest hose, there is a cloud of smoke about 6-foot high and six-foot wide covering the whole bike. I cant even see the seat. \\ | ||
+ | |||
+ | Hose, hose, hose. My buddy is not home. Where is the damn yard faucet? There are hoses lying all over the drive. \\ | ||
+ | I follow one to the end - a sprinkler. The other end - nothing. \\ | ||
+ | Just lying in the garden. He has bore (well) water and the pump switch is inside the (locked) garage. \\ | ||
+ | |||
+ | The cloud of smoke is getting smaller, but I can't blow the flames out, or get a glove in there to beat them out, behind the battery. \\ | ||
+ | The fire is burning quite well in there. \\ | ||
+ | I am getting ready to stand back and watch a bike I have owned for 31 years and just spent six months restoring go up in flames before my eyes. \\ | ||
+ | The English language simply does not have the words to describe that feeling. \\ | ||
+ | |||
+ | I ain`t taking this lying down. Around the side of the house, bucket, bucket, bucket. \\ | ||
+ | My buddies` home brewing kit is there, with 5-gallon plastic buckets for washing bottles in... with water in one of them. \\ | ||
+ | Kersplash, problem solved. Whew, no English words to describe that feeling either. \\ | ||
+ | |||
+ | At first, I am cursing the recently installed Accel regulator, which is too hot to touch. \\ | ||
+ | There were plenty of English words to describe that feeling. Many starting with F and C and of Saxon origin. \\ | ||
+ | |||
+ | Then I am checking out the fried wiring to the ignition switch and see the horn bracket has broken from vibration. \\ | ||
+ | (the one between the two cylinders, right above the ignition switch) \\ | ||
+ | The highly conductive metal horn bracket has lobbed straight onto those bare screw connections on the back of the ignition switch. \\ | ||
+ | (right on , of course, the main power wire from the battery). More words of Saxon origin. \\ | ||
+ | |||
+ | Lucky my BM riding buddy was not home to see all this. And he lives uphill from my place, so I roll the bike home and into the shed. \\ | ||
+ | Had time before work to strip off the seat and ignition switch and remove the battery. \\ | ||
+ | Fried wires up through the main loom from the battery area to the ignition switch. \\ | ||
+ | Looks like I can splice in new wires without replacing the whole loom. Bummer, original unmolested factory loom - well, was. \\ | ||
+ | |||
+ | And as usual, the circuit breakers did not break. Or were breaking temporarily and resetting straight away - causing that misfire, I would bet money. \\ | ||
+ | I will be wiring an inline fuse into that main battery wire. \\ | ||
+ | Oh well, just another day with the Ironhead. Gotta go and buy some heat shrink tubing. \\ | ||
+ | |||
+ | The bracket is rubber mounted. \\ | ||
+ | The part that broke was the top part that bolts to the big heavy bridge bolted between the two heads, and the rubber bobbin attaches to it. \\ | ||
+ | So the actual horn and small bracket are isolated from the vibes. \\ | ||
+ | It broke right where the thin (.080" or so) bracket stuck out past the heavy (3/8") bridge. \\ | ||
+ | The bracket is sort of roughly chromed so it looks like there was some hydrogen embrittlement from the chroming. \\ | ||
+ | That combined with HD vibration. Poor design that lets the bracket flex in use and the repeated heat cycles of the between the cylinder location. \\ | ||
+ | The break is crystalized and you can see it was broke 3/4 of the way through for a long time before. \\ | ||
+ | A TIG weld repair with gussets should work to stop future flexing, and a properly insulated ignition switch set up will stop it from happening again. \\ | ||
+ | |||
+ | See that broken horn bracket right where my finger is pointing in the pic below. \\ | ||
+ | And the bare terminals right below it. And the shiny copper wire direct from the battery, that used to have red insulation on it. \\ | ||
+ | Well toasted. Nothing to insulate those terminals if something goes wrong. \\ | ||
+ | In the third pic below is what fractured and fell down on top of those bare hot terminals. \\ | ||
+ | |||
+ | {{:techtalk:ref:elec:74_xlh_wiring_meltdown_1_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) {{:techtalk:ref:elec:74_xlh_wiring_meltdown_2_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) {{:techtalk:ref:elec:74_xlh_wiring_meltdown_3_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) \\ | ||
+ | |||
+ | This is all that was left of the main power wire from the battery to the ignition switch. \\ | ||
+ | A good foot of copper simply vaporized and disappeared. \\ | ||
+ | |||
+ | {{:techtalk:ref:elec:74_xlh_wiring_meltdown_4_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) \\ | ||
+ | |||
+ | Nearby wires were well fried too, the ones going to the breakers after they leave the switch in the first pic below. \\ | ||
+ | The others are the other end of the main loom going under the seat post area. \\ | ||
+ | |||
+ | {{:techtalk:ref:elec:74_xlh_wiring_meltdown_5_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) {{:techtalk:ref:elec:74_xlh_wiring_meltdown_6_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) {{:techtalk:ref:elec:74_xlh_wiring_meltdown_7_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) \\ | ||
+ | |||
+ | Took some fixing. \\ | ||
+ | I opened the melted outer cover, replaced the fully toasted wires, patched some singed ones with fusion tape and Nitto tape, heat shrink and whatever it took. \\ | ||
+ | Had to solder some new sections in some. \\ | ||
+ | |||
+ | {{:techtalk:ref:elec:74_xlh_wiring_meltdown_8_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) {{:techtalk:ref:elec:74_xlh_wiring_meltdown_9_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) \\ | ||
+ | |||
+ | The rat's nest under the seat survived unscathed except the wires to the ignition breaker and lights breaker. \\ | ||
+ | I added another fourth breaker, a 30amp job, right next to the battery so this cant happen again. \\ | ||
+ | The closeness of wires and terminals and steel frame and fender parts is absolutely terrifying. \\ | ||
+ | But I figure the master breaker right at the battery will prevent any meltdown if a bottle cap or something should blow in there off the road and arc those terminals. \\ | ||
+ | |||
+ | {{:techtalk:ref:elec:74_xlh_wiring_meltdown_10_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) {{:techtalk:ref:elec:74_xlh_wiring_meltdown_11_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) \\ | ||
+ | And the ignition switch now has a cocoon of fusion tape and Nitto tape to insulate those terminals plus some super heavy duty heat shrink to go over top off all that. \\ | ||
+ | Also the patched and spliced main loom with a couple of layers of Nitto tape wound around it in opposite directions. \\ | ||
+ | And the TIG welded horn bracket with a strengthened patch so hopefully it won`t break again. \\ | ||
+ | {{:techtalk:ref:elec:74_xlh_wiring_meltdown_12_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) {{:techtalk:ref:elec:74_xlh_wiring_meltdown_13_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=277021&page=4)) \\ | ||
\\ | \\ |