I think the consensus generally is that best results are with stock wires , some will differ I'm sure ..
I use E3's in the riding mower , always stuck with HD plugs and wires , mainly cause they work ..

JtB

 

For the Milwaukee 8s I don't think it really matters anymore, but for us twin cams, stock wires and plugs were best because of knock sensing strategy used for the bikes. Think the new ones actually use a knock sensor, but I haven't really gutted an m8....yet

 

Imo, only a dyno would see a minimal difference if any. M8's being dual plugged, the difference would probably be even less. When replacing, I switched to screaming eagle plugs & wires on previous bikes, indexed for optimum burn. Probably go with se on this one, mainly for looks.

 

So, you would consider buying E3 spark plugs. Got any interest in some farm land in Southern Cali?

All fun aside. Put a set of NGK iridium plugs in it, and forget about plugs for 30k miles. CR9EIX. The SE plugs Harley sells are just AC iridium's for a premium price.

As for the wires, if you don't damage them getting em off the plugs, they should be fine. Just put some dielectric grease on the end of the plug and snap them back on the new plugs.

 

So, you would consider buying E3 spark plugs. Got any interest in some farm land in Southern Cali?

All fun aside. Put a set of NGK iridium plugs in it, and forget about plugs for 30k miles. CR9EIX. The SE plugs Harley sells are just AC iridium's for a premium price.

As for the wires, if you don't damage them getting em off the plugs, they should be fine. Just put some dielectric grease on the end of the plug and snap them back on the new plugs.

Just put my NGK Iridiums in my bike Saturday. I'll likely sell the bike before I need to change plugs again.

Sent from my SM-N986U using Tapatalk

 

I never seen the worth of spending tons more for a spark plug. Its not worth the 1 or 2 hp gain, if that, that you get. Cleaner burn maybe...

Better wires if they are in a color you like. I did screaming eagle plugs and wires. They were all a little more than oem.

Sent from my SM-N970U using Tapatalk

 

Go with the stock plugs and a 6 pack. You will be happier

 

I highly doubt you'll notice any difference with those plugs compared to the stock plugs. When I first changed the plugs on my 09 the parts guy wouldn't sell me anything other than the stock plugs. I asked about the screamin eagle plugs and he said it's not worth the extra money. When I bought a new S&S 124 crate motor it came with champion plugs that cross reference to the stock plugs. Buy whatever you like but I would spend the extra money on gas for the tanks rather than plugs and wires that you cant tell are on the bike

 

Stock plugs and wires work just fine, getting anything other then that your just wasting money. There is no performance gain from doing a plug/wire upgrade.
IMO people change the plugs to often in their bikes as long as the plugs have a light tan color then the bike is running like it should, just clean the plugs and check the gap and put them back in.
When was the last time you changed the plugs in your car ? Now a days plugs can go a 100,000 to 200,000 miles in a automobile as long as it has no running issues.
I changed my plugs 6 years ago and put the old plug in the tool kit just incase. The bike still runs like new. JMO

 

Have used E-3 plugs in a early 2000's twin cam. Noticeable cold start difference. Stuck with them for years. The heritage with an evo did not seem to show any difference.

 

Time for some maintenance on my 17' RGU. Considering purchasing these new E3.39 Spark plugs. Many times it is difficult to get a consensus about what works best on a Harley. Does anybody have experience using these plugs? Very interested in 1st-hand opinions on their performance. Like just about everything else, I read mixed reviews. Also, spark plug wires. What do you believe are the best spark plug wires based on enhanced performance, or are stock plug wires sufficient? Please share!
Thanks!

God Bless, ride safe!
Semper Fi

My Indy only uses Factory HD plugs and won’t use any other brand....and it’s because “they always work”. That speaks volumes....

 

IMO use either H-D or equivalent. NGK manufactures the H-D Plug

 

Some have had issues with deposits building up on the E3's I suspect they are much more susceptible to it than the iridium's.

E3 Spark Plugs–Not such a good idea

 

I had E3 Plugs in My 12 Custom and just replaced them with the NGK Iridium's yesterday. The E3's were black with deposits. When I went for a ride last night I felt My Glide was running smoother and better.
Guess I will stick with the NGK's.
Mike U.

 

Copper is better. Silver is the best. There is always give and take. Improve on one thing but loose on the other end. fancy Plugs will last longer but hold the heat and can cause detonation problems. Sure your fancy plugs can last longer, avoid corrosion, and help you stay sober because you spent all your beer money on fancy plugs, but the truth is, your parts guy don't tell you because he probably doesn't know any better. Thermal conductivity is "vital " to prevent pre ignition detonation. AKA "GRENADING" an engine and builders worst nightmare.The more efficiently a spark plug is able to dissipate the heat being accumulated, the less likely you are to occur pre ignition detonation witch can cause substantial damage to your high performance and racing engines. In essence, Those spark plugs you thought were obsolete, are actually better for performance and longevity of your engine. What do you want to last? Your plugs, or your engine? 4 bolts, an electrical plug, a breather hose, and a quick disconnect gas line is a small price to pay to keep plugs fresh and new rather than causing more problems to your engine. Takes about 20 min to swap out fancy plugs sober. Buy the cheep ones and you too can take 4 hours to do the job drunk and still have money left over for aspirin in the morning. From a M8 guy who blows money on the best but plugs? Don't ask a parts guy, ask an experienced performance mechanic that actually maps these babies for performance.rather than just swapping parts. Anyone can build an engine and make it run. Few can make that same engine sing.

 

I use stoke HD plugs (6R12) with Magnecor reds leads on both my bikes.

 

three electrodes block the flame front and cause buildup, resulting in misfires.

the best plug i ever used in my evo were made by Beru, but i can't find them anymore. they had a silver core and were only about 8 bucks a piece.
popular with german manufacturers mostly and made where the sauerkraut is plentiful

 

Here is a good YouTube video about upgrading to Screaming Eagle plugs and wires.
It should answer any questions.

 

There are many reasons why manufacturers say one plug is better than another. One wire better than another. Think about it. The manufacturer doesn't care what is best for you. The mechanics, dealers, parts guy, are all just giving you the information they were told. by the manufacturers and it is not necessarily in your best interest. There focus is on longevity, compliance, environment, Warrantee, PROFIT! etc. They are not looking out for you. I want you to buy my product and I need it to not only last but to perform. In addition, I need to be compliant with a whole range of entities from environmentalists, to bureaucrats, etc. As a consumer, I want the best performing components in my ride. I will pay top dollar for the best. There are some expensive plugs out there but it does not mean they are great. A spark plug is a throw away item. You want it to last 100,000 miles? Good for you. Buy into the hype of longevity rather than performance. Iridium is far from superior to displace heat and conduct electricity. Silver is best for both. I would rather change my plugs once or twice a year than deal with other issues caused by longevity plugs. Nology is a great plug. No resister, made with silver. Why no resister? Why would I want less spark when I want a constant strong spark? IDK if there is a better silver spark plug out there but nology B2S plugs meet everything I am looking for in a spark plug. Best performance I can get, won't cause additional problems down the road, don't break the bank, consistency, reliability, performance, etc. I don't want a durable plug that lasts. I want the best right now. Stop listening to the manufacturers and all of their followers who researched nothing but what manufacturers put out. Reputable performance engine builders who are not out to profit off of a plug but rather profit off of performance, consistency, reliability, and are looking to be the best are the way to go. Brisk makes a silver plug as well but I have heard first hand horror stories of them coming apart so I stay with Nology.

 

The money you spend, for the return you get, it's definitely not worth the money!!!!
I still run stock HD plugs, I do have the fat red HD wires, but they were for looks...
I have had my share of Harley's over the years, I have dealt with ignition systems, spark plugs and wires....
I'm so old I can remember when splitfire spark plugs came out, ac rappid fires, and let's not forget the accell u grooves, back in my drag race days, I tried them all spark plugs wires, even ignition systems from my drag car. Just to try to get that edge. I will say this, every vehicle I have has Taylor wires on it.
Now the technology is even better, with more choices, and all have different claims. But at the end of the day even with a different set of plugs in a different set of wires oh, the money you spent still only brings you a couple of horsepower if that,
My 96" was replaced with a hot 103, even with pistons, cams, head work and a custom **** tune, I still run the stock spark plugs.....
To me spark plugs are like the old debate, which oil is better.... everybody's going to have some kind of opinion🤣🤣

This info comes from an old guy, I am so old I can remember when Michael Jackson was black......
Covers mouth and heads to the corner
😯😯