Coil issues?
#1
07-04-2018, 06:36 PM
Coil issues?
Here's the details, 2003 Super Glide, carbed bike, 43,000 miles on it, zero issues up to now. Here's the story, several weeks ago I went on a 250 mile ride, no issues all day, maybe 80 degrees out. We gas up and head home, about 20 miles later the bike dies. Idiot lights still work, oil light comes on (as I coast to a stop). Stop on the side of the road, try and start it up it coughs sputters and nothing. Wait a minute and it fired right up, goes about 100 yards and it dies. Same story trying to get it started, goes about a mile and dies. This time I turn the key off, turn it on and it fired right up, this time makes it about 13 miles, dies again. This goes on for a while, I eventually make it home. I drain the gas (assuming it's bad gas since I had no issues until I filled up) check the carbs, pull the petcock, everything looks good. I ride it around for the last few weeks (to work and back, a few miles is all) no issues. Then just this afternoon i ride around for about an hour around town, maybe mid 80's, it does it again. It died near a gas station so I got off and got something to drink, then it fired right up and I make it home . I tested the coil as soon as I got back and for the primary resistance I got .9 Now that it is cooled off I'm still getting .9 ohms, spec is between .5 and .7 .secondary resistance was 6.5 hot and cold (20k setting, which I'm guessing means 6500, (spec is 5500 - 7500) technically the coil is out of spec , but would it be out of spec enough to cause issues? It seems like it only happens when the bike gets warm.
Also I don't know if it matters, but the oil has been changed within the last few weeks. so I've had the issue with old oil and I've had the issue with new oil.
Also I don't know if it matters, but the oil has been changed within the last few weeks. so I've had the issue with old oil and I've had the issue with new oil.
Last edited by wyotana; 07-04-2018 at 07:29 PM.
#3
07-05-2018, 08:28 AM
Bad gas was originally my thought, but I completely drained the tank, carbs, fuel line, everything. And when I filled up again it was at a different gas station in a different own. I figured the chances of it being bad gas two times in a row at two different gas stations in two different states state had to be crazy. on top of that I had to have gone at least 60 miles on this new tank of gas before I had an issue.
#4
07-05-2018, 06:33 PM
Tourer
When you drained the gas did you remove the fuel petcock and check the filter? I had a similar problem last year when I would get under half a tank of gas it would act up and found my gas tank liner was peeling and clogged my filter. I’ve also had a coil problem years ago on my evo but once it was dead it was dead. No spark at all and while I don’t remember checking the resistance I do remember checking power and ground to it which were good.
#5
07-05-2018, 06:37 PM
When you drained the gas did you remove the fuel petcock and check the filter? I had a similar problem last year when I would get under half a tank of gas it would act up and found my gas tank liner was peeling and clogged my filter. I’ve also had a coil problem years ago on my evo but once it was dead it was dead. No spark at all and while I don’t remember checking the resistance I do remember checking power and ground to it which were good.
#6
07-05-2018, 06:46 PM
Tourer
Have you checked the ignition switch wiring? If there’s any corrosion it could cause a loss of connection. My tank ignition switch had to be replaced because of corrosion. Also might just want to check the battery cables if yours are like mine under the seat my negative ground wire seems to get lose on its own at times on the backbone of the frame. It’s going to be hard to diagnose unless you can get it to act up while you can work on it and not miles from home.
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wyotana (07-06-2018)
#7
07-05-2018, 06:54 PM
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#8
07-05-2018, 09:47 PM
Have you checked the ignition switch wiring? If there’s any corrosion it could cause a loss of connection. My tank ignition switch had to be replaced because of corrosion. Also might just want to check the battery cables if yours are like mine under the seat my negative ground wire seems to get lose on its own at times on the backbone of the frame. It’s going to be hard to diagnose unless you can get it to act up while you can work on it and not miles from home.
#9
07-06-2018, 02:19 PM
Seasoned HDF Member
A common issue with older bikes is the crank sensor goes bad. It has a magnet in it that loses strength when it gets hot. (all magnets do to some extent) Weak magnet means seak crank signal. Bike heats up, signal goes away. Bike quits. Cools off. Signal comes back. Bike runs. Coils usually don't go bad and in this case, There is really 2 separate coils in the coil (bike is single fire). This means for the motor to quit both coils would have to die..
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wyotana (07-06-2018)
#10
07-06-2018, 03:01 PM
A common issue with older bikes is the crank sensor goes bad. It has a magnet in it that loses strength when it gets hot. (all magnets do to some extent) Weak magnet means seak crank signal. Bike heats up, signal goes away. Bike quits. Cools off. Signal comes back. Bike runs. Coils usually don't go bad and in this case, There is really 2 separate coils in the coil (bike is single fire). This means for the motor to quit both coils would have to die..