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DualFire or Single Fire Coil

e7171

e7171

Member
Does anybody know for sure if a 1972 Sportster would be a dual or single fire system. I want to convert it to electronic ignition so I don't have to mess with points anymore. Ant want to make sure I buy the right kit.

I am pretty sure it is dual fire, but I'm wondering if anybody knows for sure.
 
Thanks for the info. I've been playing with electronics for so long I forgot about the I forgot about the single or dual points distributors.
 
Thanks for the info. It makes for some interesting reading. I always wondered exactly what the differences were.
 
e7171 said:
Does anybody know for sure if a 1972 Sportster would be a dual or single fire system. I want to convert it to electronic ignition so I don't have to mess with points anymore. Ant want to make sure I buy the right kit.

I am pretty sure it is dual fire, but I'm wondering if anybody knows for sure.
Click to expand...

When I redid my '91 Dyna, I went with the Spyke electronic single fire ignition module and the Spyke high output single fire coil. This replaced the stock HD system. Also eliminated the VOES on the carb, so that vacuum line needs to be plugged.

Much happier with the single fire.

TQ
 
TQuentin1 said:
When I redid my '91 Dyna, I went with the Spyke electronic single fire ignition module and the Spyke high output single fire coil. This replaced the stock HD system. Also eliminated the VOES on the carb, so that vacuum line needs to be plugged.

Much happier with the single fire.

TQ
Click to expand...


TQ when you say happier with single fire , what do you mean.
There was a lengthly discussion about this last year and I could not think of any reason to switch over to single fire for my 95.

What improovement have you noticed ???
 
dangerdan said:
TQ when you say happier with single fire , what do you mean.
There was a lengthly discussion about this last year and I could not think of any reason to switch over to single fire for my 95.

What improovement have you noticed ???
Click to expand...


The Spyke system I bought (and I suspect the other aftermarket electronic ignition systems) is a "multi-spark" (two hits) single fire system. Even though it is firing twice, it is only firing one cylinder - the one on its compression stroke. No "wasted" spark to the cylinder on its exhaust stroke.

I just don't like the idea of firing any unburnt fuel in the cylinder on its exhaust stroke that might cause unnecessary resistance load on the piston. But with all the changes I made to the bike when I redid it ('99), it would be hard to attribute how well the bike runs to any ONE change. The single fire coil is like this:

• Capable of 80,000 Volt output.
• Extremely fast rise times.
• Full voltage output in multi-spark.
• High amperage output.
• Fires at low voltages.
• Easy starting.
• Section bobbin construction.

Here is the flier on the unit I have on the little bike, but it is now discontinued. They have their new AIS sytems instead:

http://www.spyke1.com/manuals/scsman.pdf

TQ
 

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That looks like a pretty good system TC, I've been thinking on going with a single fire system on my 84 FXR, I agree with you about dumping unburnt fuel.
 
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