Single fire ignition.
Thread Starter
|
Seasoned HDF Member
Joined: Sep 2012
Posts: 6,570
Likes: 590
From: almost there
Single fire ignition.
I got this info off the box and know there is several opinions on this so thought Id post it. I was thinking about up grading my Ignition to the Ultima which looks to be exactly like the Dyna 2000i, for 1/2 the price.
Quote:
Harley Davidson’s have two cylinders and of course two spark plugs. When one piston is compressing or firing the other is either on its way down or on its way back up. The problem is that when the correct spark plug is firing so is the other one, this is dual fire; both plugs fire at the same time even though only one is needed. The problem is that there may be fuel remaining in the other piston which will ignite causing the engine to fight itself by trying to pushing the upward moving piston back down again. This affects you in many ways, increased vibration, lower fuel economy, your plugs where out twice as fast, hard starting, lower horse power and lower torque. But single fire only fires one plug at a time, the one that should be fired, the one when the piston is fully compressed and full of fuel mixture. The other spark plug sits and waits its turn. So, you get the opposite of dual fire; less vibration, better fuel economy, your plugs last twice as long, easier starting, more horsepower and torque.
Quote:
Harley Davidson’s have two cylinders and of course two spark plugs. When one piston is compressing or firing the other is either on its way down or on its way back up. The problem is that when the correct spark plug is firing so is the other one, this is dual fire; both plugs fire at the same time even though only one is needed. The problem is that there may be fuel remaining in the other piston which will ignite causing the engine to fight itself by trying to pushing the upward moving piston back down again. This affects you in many ways, increased vibration, lower fuel economy, your plugs where out twice as fast, hard starting, lower horse power and lower torque. But single fire only fires one plug at a time, the one that should be fired, the one when the piston is fully compressed and full of fuel mixture. The other spark plug sits and waits its turn. So, you get the opposite of dual fire; less vibration, better fuel economy, your plugs last twice as long, easier starting, more horsepower and torque.
Seasoned HDF Member
Joined: Aug 2007
Posts: 8,198
Likes: 3,087
From: NW AR
The OEM setup is properly referred to as "waste spark." It is a good system. A single fire MIGHT provide a very slighly smoother idle, but that's it. I don't think anyone has ever shown a power gain, better fuel economy, etc. from one. Complexity goes up as well, as you now have 2 separate coils (even if they look like 1 coil) instead of 1 coil.
People like the Ultima ignitions. I would consider one if I needed it, but would hook it up to run on a stock coil (waste spark.)
People like the Ultima ignitions. I would consider one if I needed it, but would hook it up to run on a stock coil (waste spark.)
Road Master
Joined: Sep 2013
Posts: 1,054
Likes: 441
From: Tejas
I've been running single fire ignitions for about 8 or 9 yrs now at least on both my shovel and my dresser. Both are larger motors of 93" and 113" and both run great using them. One is a cone module (shovel) and the dresser has the module under the cover. Both are Crane HI-4 systems, one being the HI-4E.
I run Dyna twin tower coils on the shovel (dual plugged heads) and the Crane all in one coil on the dresser.
Griz
I run Dyna twin tower coils on the shovel (dual plugged heads) and the Crane all in one coil on the dresser.
Griz
Road Warrior
Joined: Jul 2013
Posts: 1,476
Likes: 5
From: Florida
Aside from the single fire feature, the "improvement" would be being able to fine tune your timing curve, as well as a few other less important features.
Thread Starter
|
Seasoned HDF Member
Joined: Sep 2012
Posts: 6,570
Likes: 590
From: almost there
I would think Fine tuning would be a plus for the fine line between pinging and advancement for a performance motor. I have 10.1 with shaved heads so a professional tuner might be able to dial it in better. I have the Dyna S with tweaked springs and weights now.
Trending Topics
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
The quote is BS, pure and simple, yes, there may possibly be a TINY amount of fuel in the exhaust gases of the other cylinder but with no compression going on and no fresh air to burn with it the likelihood of combustion occurring is on a par with being served at a gas station by Elvis and Buddy Holly.
Gas is only there to ignite the air......there is 13 times more air than fuel in a combustion explosion in an automobile motor. Exhaust gases don't contain enough air to ignite.
Gas is only there to ignite the air......there is 13 times more air than fuel in a combustion explosion in an automobile motor. Exhaust gases don't contain enough air to ignite.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Thread Starter
|
Seasoned HDF Member
Joined: Sep 2012
Posts: 6,570
Likes: 590
From: almost there
Thanks Spanner. Also, would the better ignition "Altima- Dyna 2000i"give me any better timing for my High compression 10.1, setting advance before pinging starts?
Last edited by aces&8s; Mar 11, 2014 at 03:30 PM.
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
Adjustable advance curves are never a bad thing on a tweaked motor....final ign timing is down to where you set it to.