Duel plug heads????
Novice
Joined: Jan 2011
Posts: 15
Likes: 0
From: Keller, TX
I found this post while doing a little google searching online. No performance upgrade from dual plug heads? I disagree and have the bike to back it up.
Harley XL1200 "S". This was a limited production bike that had several odd things done to it. 1) yep, dual plug heads, 2) Screamin Eagle cams (from the factory), 3) Screamin Eagle ignition (not from the factory), 4) Supertrapp pipes (not from the factory), 5) adjustable suspension front & rear (from the factory, 6) engine color scheme and finish is different (from the factory), 7) tach & speedo (factory), 8) tripple disc brakes (factory), 9) my paint scheme (not factory)........so on and so forth. I don't know too many HD's out there other than the 103" Screamin Eagle that can hang with me. Believe me, I've picked fights with most that were willing.
The only thing I have left is a Mikuni carb upgrade. Other than that she's plenty fast, for a Sportster, for a Harley, and for a bike that you'd have to look long and hard to find one. I have put several posts on here looking for other owners of a "S" model and no one has piped up. I hate to be one to disagree but I have the bike to back up my claim. HUGE improvement over any stock Sportster when it comes to performance, sound, looks, etc.
Harley XL1200 "S". This was a limited production bike that had several odd things done to it. 1) yep, dual plug heads, 2) Screamin Eagle cams (from the factory), 3) Screamin Eagle ignition (not from the factory), 4) Supertrapp pipes (not from the factory), 5) adjustable suspension front & rear (from the factory, 6) engine color scheme and finish is different (from the factory), 7) tach & speedo (factory), 8) tripple disc brakes (factory), 9) my paint scheme (not factory)........so on and so forth. I don't know too many HD's out there other than the 103" Screamin Eagle that can hang with me. Believe me, I've picked fights with most that were willing.
The only thing I have left is a Mikuni carb upgrade. Other than that she's plenty fast, for a Sportster, for a Harley, and for a bike that you'd have to look long and hard to find one. I have put several posts on here looking for other owners of a "S" model and no one has piped up. I hate to be one to disagree but I have the bike to back up my claim. HUGE improvement over any stock Sportster when it comes to performance, sound, looks, etc.
Club Member
Joined: Mar 2009
Posts: 66,126
Likes: 51,453
From: Niles Canyon Ca.
This may come as a complete shock to many folks but dual plugs ain't what most think. We have dual-plugged Pans, Iron & Evo XL's, Shovels, Evo's and Twin Cams, over the almost 3 decades we have been in business.
Small engines, as well as large powerplants.
NEVER had we EVER experienced anything earth-shattering, in regards to doing so, while dyno testing/tuning later, and trust me, we shook the trees.
Machine heads, 4 plugs, 2 sets of wires, multiple coils, specialty coil mounts, usually along with a single fire ignition.
Let's see...........650.00 plus dollars for no more torque, or hp, in a street driven bike.
Think I'd rather have a bar of soap.
Scott
Small engines, as well as large powerplants.
NEVER had we EVER experienced anything earth-shattering, in regards to doing so, while dyno testing/tuning later, and trust me, we shook the trees.
Machine heads, 4 plugs, 2 sets of wires, multiple coils, specialty coil mounts, usually along with a single fire ignition.
Let's see...........650.00 plus dollars for no more torque, or hp, in a street driven bike.
Think I'd rather have a bar of soap.
Scott
You don't get screaming big performance gains of any kind , on a day to day street rideable shovel and todays gas the gain is in basic tuning like starting , knock issues and plug life is what I've found . When you could get 96 oct. gas anywhere no gain , fast forward 25yrs and yes I believe there is . Dual plugging the heads cost me $55 a hole when a valve job is being done anyway and I insert the holes my self & 4 pole coils are available now for dual fire ing. Single fire on a stocker is a waste I agree , but it does look real good on bike set up right .
Last edited by TwiZted Biker; Jan 16, 2011 at 06:24 PM.
Road Master
Joined: Oct 2012
Posts: 864
Likes: 28
From: Mt. Pleasant SC
This may come as a complete shock to many folks but dual plugs ain't what most think. We have dual-plugged Pans, Iron & Evo XL's, Shovels, Evo's and Twin Cams, over the almost 3 decades we have been in business.
Small engines, as well as large powerplants.
NEVER had we EVER experienced anything earth-shattering, in regards to doing so, while dyno testing/tuning later, and trust me, we shook the trees.
Machine heads, 4 plugs, 2 sets of wires, multiple coils, specialty coil mounts, usually along with a single fire ignition.
Let's see...........650.00 plus dollars for no more torque, or hp, in a street driven bike.
Think I'd rather have a bar of soap.
Scott
Small engines, as well as large powerplants.
NEVER had we EVER experienced anything earth-shattering, in regards to doing so, while dyno testing/tuning later, and trust me, we shook the trees.
Machine heads, 4 plugs, 2 sets of wires, multiple coils, specialty coil mounts, usually along with a single fire ignition.
Let's see...........650.00 plus dollars for no more torque, or hp, in a street driven bike.
Think I'd rather have a bar of soap.
Scott
Stage III
Joined: Oct 2012
Posts: 3
Likes: 0
From: springville NY
Perfect timing! I agree on the sweet spot being where Twisted suggests. I still run circut breaker and a static time after 30 years on my 73 shovel, never a miss and slightly retarded is an easier start. find out what cam you have as this may affect this. if you have no info on your motor, take a peek inside this winter.
Advanced
Joined: Apr 2010
Posts: 58
Likes: 1
From: Piqua, oHIo
I have to ask Twizted Biker, Did you intend to explain timing the ignition this way ? I have not posted before on this forum and would have preferred to do it in private, but that is backwards, I hate to say, leaving the front of the hole is retarded as the piston would be closer to TDC in which the firing would be later (retarded). Timing the ignition at the rear of the hole would fire sooner (advanced) Hate to see folks doing their timing incorrectly as that is one of the main benefits of dual plugged heads when used on a Hemi Head design
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