No spark, 1977 FLH Shovelhead
#1
No spark, 1977 FLH Shovelhead
Hello,
This is my third, and hopefully last post about this bike before I have it operating. In the other 2 posts I talk about the electrical system (solved) and the rear brake (in-progress, parts shipping). For my current issue, I believe this is my last step before I can get the bike operational, but I have an issue with sparking. It seems that no power is getting to the spark plugs to initiate that spark and fire the engines. I have tested my ignition coil (5 Ω) and the primary resistance is 4.8-5.7 Ω with a secondary resistance of 18,480 Ω. Because of these numbers I believe my ignition coil to be operational, but that leads my problem elsewhere. I have read online that a low battery could be the issue, but with ignition off I get 12.33 V and with ignition on (Light and accessories too) it is 12.16V, which I believe to be sufficient as well. This brings me to my third idea, the ignition breaker (timer) isn't sending off a signal to tell the spark plugs to fire. I got into that lower section of the bike and saw power was going through it and was moving when trying to start the engine. The bike has fuel, engine oil, transmission oil, battery connected, and any other setup that needed done previously. I was using a professional timing light as well to see if power was ever getting to the spark plugs and it seems that the ignition coil is getting power, but it isn't being distributed through the wires to the spark plugs? The bike sounds like it is trying to start when hitting the direct button and the ignition is on.
Let me know what you think,
Isaiah
This is my third, and hopefully last post about this bike before I have it operating. In the other 2 posts I talk about the electrical system (solved) and the rear brake (in-progress, parts shipping). For my current issue, I believe this is my last step before I can get the bike operational, but I have an issue with sparking. It seems that no power is getting to the spark plugs to initiate that spark and fire the engines. I have tested my ignition coil (5 Ω) and the primary resistance is 4.8-5.7 Ω with a secondary resistance of 18,480 Ω. Because of these numbers I believe my ignition coil to be operational, but that leads my problem elsewhere. I have read online that a low battery could be the issue, but with ignition off I get 12.33 V and with ignition on (Light and accessories too) it is 12.16V, which I believe to be sufficient as well. This brings me to my third idea, the ignition breaker (timer) isn't sending off a signal to tell the spark plugs to fire. I got into that lower section of the bike and saw power was going through it and was moving when trying to start the engine. The bike has fuel, engine oil, transmission oil, battery connected, and any other setup that needed done previously. I was using a professional timing light as well to see if power was ever getting to the spark plugs and it seems that the ignition coil is getting power, but it isn't being distributed through the wires to the spark plugs? The bike sounds like it is trying to start when hitting the direct button and the ignition is on.
Let me know what you think,
Isaiah
#2
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rockher_man (09-01-2024)
#3
#5
Join Date: Jun 2013
Location: St. Catharines, Ontario
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Don't start throwing parts at it. A coil will produce a spark down to 10 volts. What is the voltage while cranking? Try this test. remove 1 plug and make sure the metal shell is grounded, on an unpainted surface. try to start, observe if there is a spark at the electrode.
Please remind us what ignition you have, points or electronic?
Please remind us what ignition you have, points or electronic?
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pgreer (09-01-2024)
#6
Don't start throwing parts at it. A coil will produce a spark down to 10 volts. What is the voltage while cranking? Try this test. remove 1 plug and make sure the metal shell is grounded, on an unpainted surface. try to start, observe if there is a spark at the electrode.
Please remind us what ignition you have, points or electronic?
Please remind us what ignition you have, points or electronic?
https://4into1.com/magna-dual-fire-c...-hd-1965-2003/
#7
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#8
Join Date: Jun 2013
Location: St. Catharines, Ontario
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Take the points cover off and rotate engine until points are open , either the wide or narrow lobe. check that you have 12vdc at moving contact when the ignition switch is ON. Don't hit your start button. Test for spark by grounding the contact,( I use a screwdriver blade) take the jumper away, plug should spark
#9
#10
If you have the old style points ignition inside the round cover with two screws on the cam cover (right side of the enigne) you are ok with the 5 ohm coil. If you aren't sure, remove the two screws and have a look. The ignition (spark plugs) should fire when the points open. But are the points set to the correct gap when on top of the ignition cam lobe?
Remove the round cover with two screws on the cam cover and take a picture of what you have and post it here.
Paul
Remove the round cover with two screws on the cam cover and take a picture of what you have and post it here.
Paul
Last edited by pgreer; 09-01-2024 at 02:45 PM.
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Baird (09-01-2024)