78 FLH front cylinder not firing
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78 FLH front cylinder not firing
A very close friend of mine is having an issue with his 78 FLH Shovelhead. It is only running on one cylinder (front). A few weeks ago it was fine but we were working other issues with the battery and the solenoid which we got fixed but now it sound like it's running on one cylinder(front)? we checked spark to the plugs, changed out the Coil just in case it was a weak coil. We confirmed that it was the front because that plug and the cylinder were not getting hot. Anyone have any idea what we can troubleshoot? It was running fine about a month ago but since the solenoid went bad it's not been good. Help please!!
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From: la la land jerzey
A very close friend of mine is having an issue with his 78 FLH Shovelhead. It is only running on one cylinder (front). A few weeks ago it was fine but we were working other issues with the battery and the solenoid which we got fixed but now it sound like it's running on one cylinder(front)? we checked spark to the plugs, changed out the Coil just in case it was a weak coil. We confirmed that it was the front because that plug and the cylinder were not getting hot. Anyone have any idea what we can troubleshoot? It was running fine about a month ago but since the solenoid went bad it's not been good. Help please!!
\ switch the 2 plugs and see if now the rear that is the one not working - my guess its a bad plug
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Thanks John, we did check that both plugs were firing and the were. Do you think that the front plug is still bad? we cleaned the plugs, put them in and the rear one is the one that is fouled, the other is still clean? Sounds Crazy!!
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From: la la land jerzey
you do have the correct plugs in it right
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Thanks John, yes, the correct ones are in, I will tell him to try will try a fresh set though. it's weird because he rode it from my house to his house about a month ago and both cylinder were firing correctly. He had some electrical problems since, has a new Battery, positive cable, solenoid, and ignition switch. it starts with no issues except running on one cylinder.
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From: navarre ohio
if it is sparking rite, the problem has to be valves stuck open or not opening, or timing is way way out. both cylinders run off same carb, so that isn't the problem.
i had a shovelhead once. the front intake valve wasn't closing all the way. it would foul out the plug. the bike ran great for a couple miles on new plugs, then would run on one cyl till i changed the plug. i believe that bike still had spark on the fouled plug, but it was too week to run
was just thinking about it, the cables and stuff are rite next to the coil. could one of the plug wires be broke, or pulled out of the socket. that could make a week inconsistent spark to one cylinder, when you pull the plug to check it, the wire is held in a different position possibly letting it make contact till you put it back together, then the contact is pulled away again..
i had a shovelhead once. the front intake valve wasn't closing all the way. it would foul out the plug. the bike ran great for a couple miles on new plugs, then would run on one cyl till i changed the plug. i believe that bike still had spark on the fouled plug, but it was too week to run
was just thinking about it, the cables and stuff are rite next to the coil. could one of the plug wires be broke, or pulled out of the socket. that could make a week inconsistent spark to one cylinder, when you pull the plug to check it, the wire is held in a different position possibly letting it make contact till you put it back together, then the contact is pulled away again..
Last edited by j1mmy; Aug 23, 2013 at 09:44 PM.
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if it is sparking rite, the problem has to be valves stuck open or not opening, or timing is way way out. both cylinders run off same carb, so that isn't the problem.
i had a shovelhead once. the front intake valve wasn't closing all the way. it would foul out the plug. the bike ran great for a couple miles on new plugs, then would run on one cyl till i changed the plug. i believe that bike still had spark on the fouled plug, but it was too week to run
was just thinking about it, the cables and stuff are rite next to the coil. could one of the plug wires be broke, or pulled out of the socket. that could make a week inconsistent spark to one cylinder, when you pull the plug to check it, the wire is held in a different position possibly letting it make contact till you put it back together, then the contact is pulled away again..
i had a shovelhead once. the front intake valve wasn't closing all the way. it would foul out the plug. the bike ran great for a couple miles on new plugs, then would run on one cyl till i changed the plug. i believe that bike still had spark on the fouled plug, but it was too week to run
was just thinking about it, the cables and stuff are rite next to the coil. could one of the plug wires be broke, or pulled out of the socket. that could make a week inconsistent spark to one cylinder, when you pull the plug to check it, the wire is held in a different position possibly letting it make contact till you put it back together, then the contact is pulled away again..
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