Ignition coil?
Thread Starter
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Cruiser
Joined: Aug 2007
Posts: 189
Likes: 39
From: Guildford, UK
Ignition coil?
I'm assuming my problem is the ignition coil.....but I thought i'd check with you guys.......
Bike: 1995 Evo Fatboy
Riding to work this morning suddenly the bike cut out on one cylinder.
I limped home on one cylinder.
Just checked whether I was getting a spark on the bad (front) cylinder....and no spark.
Changed the spark plug, still no spark. (meanwhile the bike runs on the back cylinder).
Switched over the leads on the coil and then spark at the front and won't run on the back cylinder.
I'm therefore I'm assuming the ignition coil is the problem?
The coil was only new about 5 months ago, and the bike has been laid up for 3 months of that time.
Bike: 1995 Evo Fatboy
Riding to work this morning suddenly the bike cut out on one cylinder.
I limped home on one cylinder.
Just checked whether I was getting a spark on the bad (front) cylinder....and no spark.
Changed the spark plug, still no spark. (meanwhile the bike runs on the back cylinder).
Switched over the leads on the coil and then spark at the front and won't run on the back cylinder.
I'm therefore I'm assuming the ignition coil is the problem?
The coil was only new about 5 months ago, and the bike has been laid up for 3 months of that time.
Seasoned HDF Member
Joined: Nov 2006
Posts: 12,878
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From: la la land jerzey
you have a duel fire coil and both plugs fire a the same time every time so its not the coil if you switched the wires and it still started on one cylinder and did not switch the cylinder that was running to the one that did not
Could be the plug wire - could be a mechanical issue - you need to do testing and you need the factory workshop books so when asking about a part, its with the correct name its actually called so help can happen with out guessing what you actually are looking at
Could be the plug wire - could be a mechanical issue - you need to do testing and you need the factory workshop books so when asking about a part, its with the correct name its actually called so help can happen with out guessing what you actually are looking at
Thread Starter
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Cruiser
Joined: Aug 2007
Posts: 189
Likes: 39
From: Guildford, UK
I switched the HT leads at the coil.
The spark switched cylinders, so it can't be the HT leads or plugs?
The only change was the connection to the coil with the HT leads......surely that means one of the connections out of the coil is sparking and the other isn't?
The spark switched cylinders, so it can't be the HT leads or plugs?
The only change was the connection to the coil with the HT leads......surely that means one of the connections out of the coil is sparking and the other isn't?
Thread Starter
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Cruiser
Joined: Aug 2007
Posts: 189
Likes: 39
From: Guildford, UK
It was just a cheapish standard replacement.......I believe it was dual fire.
But logic says if there is only one power supply to the coil and one side emits a spark and the other doesn't......it must be a faulty coil?
But logic says if there is only one power supply to the coil and one side emits a spark and the other doesn't......it must be a faulty coil?
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Road Warrior
Joined: Oct 2011
Posts: 1,376
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From: Round Rock, TX
Assuming you have a dual fire system, if you move just one end of the plug wire from one cylinder to the other (crossed), and the miss moves, you have either a bad coil or a bad wire. If you move the entire plug wire (both ends) from one cylinder to the other, and the miss moves, the coil is good and the wire is bad. If you can't move the miss with wire switching, check compression.
Stellar HDF Member
Joined: Jan 2015
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From: ct
He swapped the plug wires at the coil ONLY and the spark switched cylinders, making both plugs good and both wires good. If he took the front wire (long) and tried it in both spots on coil and no change then that would be a different story.