no spark
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Stage II
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no spark
no spark 75 sportster all my connections are good no power to coil ? grey wire to switch has power all time black has power when switched but white wire never does should the white wire have power it runs to the coil
and i tried hookin it up direct to batt and still no spark plz help
and i tried hookin it up direct to batt and still no spark plz help
Last edited by ramey8027; Apr 3, 2009 at 10:10 PM.
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Joined: Feb 2006
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From: Houston Texas
The 12V wire goes to the ignition switch. From the 'I' terminal on the switch a wire runs to the ignition coil. This wire does not run straight,but rather winds it's way around to get to the coil. A wiring diagram will give you the path it takes.
Wire colors mean little on an older machine as they may have been replaced in the past.
There should be 12V present at the coil connection when the ignition switch is turned on. If not, then find the break in the wire or the bad connection in the wire somewhere between the coil and up stream back to the switch.
If you are getting 12V at the coil, then check your contact points gap.
The gap should be .018 for both of the ignition cam lobes.
The ignition cam has 2 lobes on it. The tall thinner one is for the front cylinder and the fatter lobe is for the rear cylinder.
Both should gap .018 in a perfect world. But the world ain't perfect, so the maximum difference between the gaps is .004. Anymore than than and you need to buy a new ignition cam.
I would suggest if the points are burned and pitted, replace them. Replace the condenser also with a new one.
After all of this has been done and you still have no spark at all, then it may be the coil is bad.
There is no way to test a coil except for substituting a new one in place of the old. You can measure the resistance of the windings with an ohmmeter, and that is about all you can do.
The resistances should be in the following range:
Primary resistance 4.7 to 5.7 ohms.
Secondary resistances 16,000 to 20,000 ohms (16K to 20K)
Now I will say I have seen a lot of coils in my time. Coils do fail I guess, but I have never seen one myself. So it is a rather rare thing to have a bad one. They crack over time and water can get inside.
But, that said, the coil is the absolute last thing I would replace in an ignition system.
Check back in when you have had a good close look at those points and checked the wires for 12V. If you have 12V at the switch you should have 12V at the coil as well........... pg
Wire colors mean little on an older machine as they may have been replaced in the past.
There should be 12V present at the coil connection when the ignition switch is turned on. If not, then find the break in the wire or the bad connection in the wire somewhere between the coil and up stream back to the switch.
If you are getting 12V at the coil, then check your contact points gap.
The gap should be .018 for both of the ignition cam lobes.
The ignition cam has 2 lobes on it. The tall thinner one is for the front cylinder and the fatter lobe is for the rear cylinder.
Both should gap .018 in a perfect world. But the world ain't perfect, so the maximum difference between the gaps is .004. Anymore than than and you need to buy a new ignition cam.
I would suggest if the points are burned and pitted, replace them. Replace the condenser also with a new one.
After all of this has been done and you still have no spark at all, then it may be the coil is bad.
There is no way to test a coil except for substituting a new one in place of the old. You can measure the resistance of the windings with an ohmmeter, and that is about all you can do.
The resistances should be in the following range:
Primary resistance 4.7 to 5.7 ohms.
Secondary resistances 16,000 to 20,000 ohms (16K to 20K)
Now I will say I have seen a lot of coils in my time. Coils do fail I guess, but I have never seen one myself. So it is a rather rare thing to have a bad one. They crack over time and water can get inside.
But, that said, the coil is the absolute last thing I would replace in an ignition system.
Check back in when you have had a good close look at those points and checked the wires for 12V. If you have 12V at the switch you should have 12V at the coil as well........... pg
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