I want to change the spark plugs on my 2008 Road King. I am looking for any recommendations on a spark plug beside what is listed in the owner’s manual? Thanks

 

I have heard good things from a few folks about the E3 spark plugs. I bought a set earlier this year and planning on trying them out my next oil change later this summer.

http://www.e3sparkplugs.com/

 

Why, what's wrong with the 6R12's?

 

Absolutely nothing wrong with them. They're the right plugs for the bike, and cheap as dirt.

 

This thread will never end. Spark plugs are as touchy of a subject as oil. I am running the E3's (and no my plugs were not worn out). And I noticed a significant difference in the "seat of the pants dyno".

 

I was thinking of getting those. But I heard rumors that they may not last. You know how rumors are....
There is also 6R12PP (platinum)

 

Semper Fi, Top. As a former airplane owner, I happen to know a lot about spark plugs and am a maintenance fanatic (I change oil, oil filter, plugs and air filter on my bike every 2500 miles). If you have the same 96" engine I have in my 2010 Street Glide, this is what you want:
- Denso Iridium Fine-Wire Spark Plugs (IXU22 gapped at 0.040") $8 each from rockauto.com
- Harley-Davidson Screamin' Eagle 10mm Phat Spark Plug Wires $20 from Harley

In terms of heat handling capacity, weakest to strongest: copper, gold, platinum, iridium (iridium will handle over 4000 degrees F., 1200 degrees more than platinum). There are basically 2 types of spark plugs: massive electrodes and fine-wires. Massive electrodes are cheaper because they are made of the lesser metals, produce asymmetrically shaped sparks and foul fairly easily. Fine-wires put out a much cleaner spark allowing for better engine performance and increased fuel economy (the Denso center electrode is only 0.4mm thick). Also, the Denso Iridium spark plug has a U-Grooved electrode that puts out a symmetrically round spark allowing for consistent spark production. Check out Denso's website:

http://www.densoiridium.com

Compared to the stock plugs, you WILL notice the difference.

 

I've run the E-3's for over 10000 miles so far. Fuel mileage went from 36 to 38 mpg and power has been good. Will change them this weekend as i'm heading to Colorado and even tho still performing excellent will be piece of mind.

 

Running the Denso Iridiums with the HD 10mm Phat wires. Like the upgrade. Stock unit's will work fine.

 

What NoCoLoco said!!!!!!!!!!!!!!!!