Single fire Ignition?
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Road Captain
Joined: Aug 2008
Posts: 550
Likes: 8
From: Twin Cities,Mn.
Single fire Ignition?
I have a 96 wideglide (Pic below) with an EV27 cam. She has a free flowing air cleaner and punched out exhaust. Stock top end.
The power difference with this cam is great! (86 TQ to rear wheel!) with no other mods due to a desire for this motor to last and last! She runs like a swiss watch. My one complaint is gas mileage. She now only gets about 36 MPG and it has been on the dyno.
Local indy said I should install a single fire ignition. He stated more gas mileage as well as power! Any experience with an ignition and my set up?
The power difference with this cam is great! (86 TQ to rear wheel!) with no other mods due to a desire for this motor to last and last! She runs like a swiss watch. My one complaint is gas mileage. She now only gets about 36 MPG and it has been on the dyno.
Local indy said I should install a single fire ignition. He stated more gas mileage as well as power! Any experience with an ignition and my set up?
Road Captain
Joined: Apr 2005
Posts: 535
Likes: 14
From: Highspire Pa
My 80" (1990 FLHTCU) got about 40 mpg with normal riding most of the time, as you twist the throttle more the gas mileage goes down. I had the Crane Hi-4 single fire ignition, but the Ultima single fire seems to work as well and it costs a lot less. My engine also had the EV-27, but also 10:1 pistons, head work with bigger valves, stronger springs etc.
I never had the modified 80" on the dyno so I can't say with certainty how much power it had. The best CV carb set up I had was put together by Wally Kerstetter in Sunbury Pa 17801. It only took a couple days and at that time was about $120. The fellow that recommended Wally said he got 42 mpg after Wally worked on his carb. http://www.harleydavcvcarbrebuild.com/
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I never had the modified 80" on the dyno so I can't say with certainty how much power it had. The best CV carb set up I had was put together by Wally Kerstetter in Sunbury Pa 17801. It only took a couple days and at that time was about $120. The fellow that recommended Wally said he got 42 mpg after Wally worked on his carb. http://www.harleydavcvcarbrebuild.com/
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HDF Community Team
Joined: Dec 2005
Posts: 5,403
Likes: 2,605
From: NC USA
Single fire will not improve mileage or power to any noticable level.
One thing about dyno tuning is that they can/will only tune for maximum performance. Most often that equates to lower economy. Sometimes you can give up a tiny bit of performance, often without any noticable lose of power, and gain a good bit of fuel mileage. Since you're tuned to the "max" performance-wise, you can de-tune slightly and help your mileage.
One thing about dyno tuning is that they can/will only tune for maximum performance. Most often that equates to lower economy. Sometimes you can give up a tiny bit of performance, often without any noticable lose of power, and gain a good bit of fuel mileage. Since you're tuned to the "max" performance-wise, you can de-tune slightly and help your mileage.
Road Warrior
Joined: Apr 2007
Posts: 1,354
Likes: 1
From: S.W. Florida
I also agree with Rufus and prodrag's comments. Been running a Dyna single fire system for some time now. Might just be me, but the bike does start easier and seems smoother than it did with the SE dual fire.
Tourer
Joined: Mar 2009
Posts: 375
Likes: 4
From: St. Peters, Missouri
Single Fire vs Dual Fire...
Single fire will not improve mileage or power to any noticable level.
One thing about dyno tuning is that they can/will only tune for maximum performance. Most often that equates to lower economy. Sometimes you can give up a tiny bit of performance, often without any noticable lose of power, and gain a good bit of fuel mileage. Since you're tuned to the "max" performance-wise, you can de-tune slightly and help your mileage.
One thing about dyno tuning is that they can/will only tune for maximum performance. Most often that equates to lower economy. Sometimes you can give up a tiny bit of performance, often without any noticable lose of power, and gain a good bit of fuel mileage. Since you're tuned to the "max" performance-wise, you can de-tune slightly and help your mileage.
Fact is, as previously mentioned, there is no gain in power, torque, or mileage going from dual fire to single fire.
No documented evidence at all. Period.
And the thought that the engine runs smoother is questionable, as well....
Here's what Nightrider has to say about the topic:
http://www.nightrider.com/biketech/h...ionmodules.htm
http://www.nightrider.com/biketech/hdseignition.htm
Don't misunderstand, I'm not saying that single fire ignition isn't the way to go for you. Do as you see fit for your machine.
I know plenty of guys who run a single fire system with no trouble
All I'm saying is that if you expect a gain in power and mileage by switching out your ignition system to single fire, you'll probably be unhappy with the results, as many have been.
The dual fire Screamin' Eagle ignition system I run has performed flawlessly, easy install, (plug and play), and costs less.
As far as your mileage, it really depends on your style of riding, and the tune of your machine....
If it were me, I'd start there....
Last edited by 98 FLHX; Nov 22, 2009 at 10:41 AM.
Thread Starter
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Road Captain
Joined: Aug 2008
Posts: 550
Likes: 8
From: Twin Cities,Mn.
Man, I sure am glad I ran it by you guys! The last thing I want to do is spend money with little or no return! Thanks for saving me a few bucks!
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Extreme HDF Member
Joined: Nov 2006
Posts: 13,389
Likes: 26
From: Windham,Maine
Years ago when Single Fire was being reintroduced to we Harley riders,I bought in.There was Zero increases in anything.Does sound like a good idea.
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Stellar HDF Member
Joined: May 2005
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From:
Have you screwed around with your carb jetting? Many tuners seem to want to put larger jets than are needed in the CV carb. Even worse are the kits, power tubes and the like that make the carb slobberingly rich.
Elite HDF Member
Joined: Oct 2005
Posts: 3,872
Likes: 83
From: Canton, Michigan
^^^ Gotta agree. Back in the early 90's there was all sorts of articles about needles, drilling, springs, jets, etc. I did a few of them. As MP replied, they made for a very rich mixture. And around 38 mpg. I've since had most of them removed, the carb 'tuned' correctly, and I get around 42-45 mpg on the highway. Similar setup (although heavier bike): SE air filter, EV27, SuperTrapp slipons, Dyna 2000 (dual fire).
Your 38 mpg could be from a number of things. Running around the city or suburbia, gunning it from stoplight to stoplight. Sitting at idle and constantly 'blipping' the throttle. It doesn't take a lot to lose a couple mpg.
The CV carb got a really bad rap back then, mostly due to the EPA restrictions. The MoCo had the jetting set very lean, so the first thing everyone did was remove the plug and adjust the mixture screw.
Homework: Top off the tank, take the bike out on the interstate and run at a constant speed for 50-100 miles. Top off the tank, and do the math.
Your 38 mpg could be from a number of things. Running around the city or suburbia, gunning it from stoplight to stoplight. Sitting at idle and constantly 'blipping' the throttle. It doesn't take a lot to lose a couple mpg.
The CV carb got a really bad rap back then, mostly due to the EPA restrictions. The MoCo had the jetting set very lean, so the first thing everyone did was remove the plug and adjust the mixture screw.
Homework: Top off the tank, take the bike out on the interstate and run at a constant speed for 50-100 miles. Top off the tank, and do the math.