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You are watching: Harley davidson spark plug gap chart


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Well time again because that plugs.The manual always makes me wonder what the ideal end the the provided spec is much better or if there"s in reality a diifference between0.038 and also 0.043 performance way on a stock 96" ?I usually just stab it in the middle and settle for 0.040 .Any think ?
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I believe that is what the mechanics at harley are hoping most will execute (split the difference and set in the middle .040-.041) because not everyone has actually the very same feel v a gap gage. One human may think he is gaping at .040 , but if that does not have actually the proper feel it could be turn off by as much as .002 to add or minus. So also though he thinks he is gaping in ~ .040 it might actually be .038 or .042.
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I don"t think there"d be any kind of performance difference between 0.038 and0.043. I would certainly go with 0.038 because if you get too wide of a space spark might not run up far. I get my NGKs in ~ 0.034 however that is since of mine turbo as soon as it puts out 8 pounds of boost at complete throttle the compression ratio is over 13.5 to one. Ns tried part screaming Eagle plugs yet they didn"t last really long and also once the gap opened up a small amount it run favor crap. Even with the NGK plugs if there are gap an ext than that misfire.:know
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This is why you"re provided a "range" for your gap. The plug will occupational fine in that range, but begin to falter, exterior of that range. If the space is also small, over there isn"t enough room for sufficient of the air/fuel mixture to get between the electrode and ground strap, so once the plug walk fire over there is a chance nothing will certainly ignite. On the various other hand, if the space is too large the spark the does show up will be weak and also may no be strong enough come ignite the charge.The recommended void is the "sweet spot" for most riders, excluding greatly modded engines and aftermarket ignition systems.
__________________________________________“When the going gets weird, the weird revolve professional....” ~ Hunter S. Thompson~R.I.P. Rubberdown. 1971-2012"Your Jedi psychic tricks will not occupational on me...... ~Misinlink-2016~2005 E.G. ClassicS&S 510 camsBaisley Oil pump springCYCO tensionersV&H FuelpakSE 3.5" pipesK&N filterFueling liftersS&S adj pushrodsSwingarm stabilizer
We have witnessed proof on engines that lug a ccp phibìc of 180, or so, that .035" on the NGK"s we use, will certainly show much more power, throughout the board.It create a an ext intense spark kernel, not enabling the raised turbulence, in the chamber, to try to punch it out.
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Scott
"Harley-Davidson speed & organization Center"Goodson H-D Cylinder Head Tooling ManufacturerCelebrating over 35 year of H-D Engine Buildingwww.hillsidecycle.com
I don"t think there"d be any type of performance difference between 0.038 and0.043. I would certainly go through 0.038 due to the fact that if you gain too broad of a gap spark might not run up far. I gain my NGKs at 0.034 however that is due to the fact that of mine turbo once it puts the end 8 pounds of boost at full throttle the compression ratio is end 13.5 to one. I tried part screaming Eagle plugs but they didn"t last an extremely long and once the space opened increase a small amount the run favor crap. Also with the NGK plugs if there are gap an ext than that misfire.:know
Do friend ride this beast often. Does it organize together well?I uncovered a spark plug graph from NGK that may be valuable for some
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Just one update...the plugs that come out were over 0.045....I waited a little long to examine my gaps and/or replace.No noticeable power or performance distinction tho.Great replies !
Hay XRTrackerThe only problem I have had actually is v the screaming Eagles sparkplugs.I ride it every possibility I get and also it is held together very well i have had nothing brake on it. I"ve had the t turbocharger on it for a year and a fifty percent so far. Turbo is from Trask performance at a Phoenix, Arizona. If You desire to gain some really serious speech RB racing. Inspect out your website.:rollinRB Racing
Same here. Had a collection and occurred a miss. Put in Autolite spark plugs and also have to be fine ever since.
__________________________________________“When the going gets weird, the weird rotate professional....”
~ Hunter S. Thompson~R.I.P. Rubberdown. 1971-2012"Your Jedi psychic tricks will certainly not work-related on me...... ~Misinlink-2016~2005 E.G. ClassicS&S 510 camsBaisley Oil pump springCYCO tensionersV&H FuelpakSE 3.5" pipesK&N filterFueling liftersS&S adj pushrodsSwingarm stabilizer
Same here. Had actually a set and emerged a miss. Put in Autolite spark plugs and also have been fine ever since.
HD plugs room made through Champion. I"ve had and also seen much more issues v Champion spark plugs then any kind of other brand, in mine lifetime.I"ve seen ONE Autolite fail.That"s just in my world. I won"t run any kind of other sparkplug climate Autolite any type of more.
__________________________________________“When the going gets weird, the weird turn professional....”
~ Hunter S. Thompson~R.I.P. Rubberdown. 1971-2012"Your Jedi mind tricks will certainly not occupational on me...... ~Misinlink-2016~2005 E.G. ClassicS&S 510 camsBaisley Oil pump springCYCO tensionersV&H FuelpakSE 3.5" pipesK&N filterFueling liftersS&S adj pushrodsSwingarm stabilizer
Suuurrre.....now ya call me...........:laughNever purchase a Champion plug in my life. Ngk, AC DELCO,only.next year i"ll go with sumthin else.
all us run,on the street or in the nitro bike is autolites,we`ve had actually NGK`s fall apart(porcelin shaters) in the nitro bike,wont use them anymore
HD plugs room made through Champion. I"ve had and also seen much more issues with Champion spark plugs then any kind of other brand, in mine lifetime.I"ve watched ONE Autolite fail.That"s simply in my world. Ns won"t run any type of other sparkplug climate Autolite any kind of more.
Stock CVO 110 Mufflers, k&n A/C, stock Heads, SE 103" BB kit, andrew 26H Cams, Mustang large Touring Seat, stock Bars, H-D Oil Cooler, 1990"s LeatherWorks in ~ Saddle Bags & amendment HD deluxe Guards, H-D Luggage rack, H-D Windshield, SE Fork Brace, SE Comp, Thunder Max A/T, S&S Lifters, Zipper"s double piston tensioners, gradual Mono pipe & 422 Shocks, SCRC 524Bagger collection up to ride comfortably ​
I noticed a popping top top decel on mine carbed 05 with the gap over .040 that went away when the space was closed to .037
I noticed a popping on decel on mine carbed 05 with the void over .040 it went away once the space was closed come .037
I have likewise had a lot of of difficulties with Champion plugs and also have no bought any type of in many years and will no buy another one.:bigbarf Autolite are an excellent plugs and also Motorcraft and the finest plugs I have actually used is Accel sparkplugs.
Whether they to speak so or not nearly all automotive plugs are resistor type plugs,if you usage an ohm meter you"ll uncover most have 4000 ohms constructed in.I don"t recognize if HD plugs space non-resistor, my old Mercedes SEC required non-resistor plugs, castle were difficult to find and also it ran favor shit w/o them..
Whether they say so or not virtually all automotive plugs are resistor form plugs,if you use an ohm meter you"ll uncover most have 4000 ohms built in.I don"t know if HD plugs are non-resistor,
my old Mercedes SEC necessary non-resistor plugs, castle were difficult to find and also it ran choose shit w/o them..
Points bikes will suffer as well, with resistor plugs and non-copper core wires.The graphite, or resistance wires are simply to absorb some of the power and take the edge off for RADIO SUPRESSION. Resistance PLUGS are likewise for radio suppression.Electronic ignitions that need suppression wires and also suppression plugs are since the ignitions aren"t built an excellent enough to withstand RFI and also EMI pulses during their own operation.With the being said, likely, any type of plugs currently made by HD space resistor, as they"re designed for their digital ignition, in addition to supression wires, which practically 100% of modern-day ignitions use.
__________________________________________“When the going it s okay weird, the weird turn professional....”
~ Hunter S. Thompson~R.I.P. Rubberdown. 1971-2012"Your Jedi mental tricks will not work on me...... ~Misinlink-2016~2005 E.G. ClassicS&S 510 camsBaisley Oil pump springCYCO tensionersV&H FuelpakSE 3.5" pipesK&N filterFueling liftersS&S adj pushrodsSwingarm stabilizer
Whether they say so or not almost all automotive plugs room resistor form plugs,if you usage an ohm meter you"ll uncover most have actually 4000 ohms developed in.I don"t understand if HD plugs are non-resistor, my old Mercedes SEC essential non-resistor plugs, lock were tough to find and it ran prefer shit w/o them..

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I think you intended 40,000 OHM"s (you slipped a "0").The bikes "spark timing" and the "coil saturation" time (time to build up sufficient current) relies on the suitable resistance to job-related the secondary electrical device properly.What ever before plugs girlfriend use... Save the resistance level the same range as share (use one ohm meter). Your engine will job-related like it to be designed too. I also like to buy a batch of plugs, and sort them according to the resistance. Then usage 2 plugs that space close come each various other (within 10K ohm"s). Both cylinders will be electrically loading the same. Save the void to the minimum next of the range... As it wears, the space increases. The correct space stays in variety longer.
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