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dual fire vs. single fire ign.

Great info in Hoople and Karl's responses. I put a Dynatec HD1 unit on my '92 Dyna Glide back about '94. I can (and have) go from single to dual fire with a flip of a dip switch. Honestly, the only difference I can tell, is the idle is a little more "lumpy" in single fire mode. I'm running a .530" lift, medium duration cam.

Breeze' experience is probably what you would "hear & feel" in the saddle only IF your engine is "built up". The actual ignition "moment" is quite short and possible electrical "coil saturation" due to doubling the firing rate (having to provide wasted spark) not allowing inductance to build/fall quickly (hysteresis) is likely not detected with Stage I mods below 5,000 RPM. :hii
 
Breeze' experience is probably what you would "hear & feel" in the saddle only IF your engine is "built up". The actual ignition "moment" is quite short and possible electrical "coil saturation" due to doubling the firing rate (having to provide wasted spark) not allowing inductance to build/fall quickly (hysteresis) is likely not detected with Stage I mods below 5,000 RPM. :hii

Interesting - and that could sort of back up some claims I've read about improved mileage when converting to single fire. Reduced spark firing power = increased fuel consumption.
In your experience is that a commonly seen issue with dual fire systems at hi-po/high rpm application, or more of a marginal / theoretical problem? Zero experience myself, but will try it out once I get my overhaul sorted out...
Speaking of which, got most of my enigne build together (with single fire ignition;)
S&S 96 cuin.jpg
 
Breeze' experience is probably what you would "hear & feel" in the saddle only IF your engine is "built up". The actual ignition "moment" is quite short and possible electrical "coil saturation" due to doubling the firing rate (having to provide wasted spark) not allowing inductance to build/fall quickly (hysteresis) is likely not detected with Stage I mods below 5,000 RPM. :hii

More "sauce for the goose" explanation and some hard numbers to boot, complements to the NRHS website:

NRHS - High Performance for your Harley Twin Cam, Evolution, Sportster or Buell!


Single vs Dual Results: Advantage = SLIGHT; Cost = A LOT! for mild state of tune Stage I. :s
 
When single fire ignitions first became popular every one had to have them so it seems. my buds back in Minnesota had me installing mostly Dynas on there bikes. The biggest problem I saw with them was the rear pick up would lay down, other than that I did not see much change tho they all claimed the bikes seemed to start easier and you could time the rear cylinder. That said a Magneto set up would be the hotter set up tho more expensive, A magneto creates more constant power in fact the higher the rpm the less break down to the ignition system
 
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