Either I'm stupid for spending the money...or I'm **** about my maintenance schedule.

Plugs are $3 bucks, each...$6 bucks, total.
I change mine with every oil change, 5000 miles.

Actually, I'm neither of the above...I do it because it's easier to remember, for me.

 

My '07 Touring Models Service Manual states to change them every 20K miles or 32K kilometers, whichever comes first.

 

2008 Street Glide change at 20k.

 

Changed out to stock plugs at 10k and noticed nothing. Just what i was looking for.

 

After I had my SERT put in...I figured I'd start fresh and put in a new set of plugs. Naturally I asked for the Screemin Eagle plugs. The tuner said just put a new set of stock plugs in cause the bike was tuned to the resistance of the stock plugs and SE plugs wouldnt be the right way to go.

I don't know crap about the resistance of a plug and tuning BUT...thats what they said. So I put two new stock plugs in. Don't know why they didn't take me for the price of the SE plugs but they didn't.

 

I changed mine yesterday at 5,200 miles. Paid $4.78 for 2 NGKs at Advance Auto Parts. I did it because I loaded a new map and I want to visualize the impact on the plugs. Otherwise, I would have waited till I hit 10,000 miles to replace them.

 

Cheap and easy to install. Do what manual recommends IMO.

 

Champion plugs are H/D plugs without the H/D. On sale for .97 cents.
http://www.nightrider.com/biketech/hdsparkplugs01.htm

 

Yep. $0.97 for the plug and 2 bucks for the HD Logo.

 

If your car or pickup can go 60k to 100k miles with out a tune up, and you don't change
spark plugs in that time frame why change them on your H-D. There is no lead in gasoline any more, most all cars and motorcycles are now fuel injected. I can see changing plugs more offten with a carbureted engines but not on a fuely dose the gap change much in 10k, what is the color on the plugs? ? ? Back in the 60s and 70s we changed a lot of spark plugs because the lead in the gas and we ran carburetor we watch the color of the plugs to check the jetting. I don't see it. I think the dealers are making money on service any way they can. I think you should check the spark plugs, and change them when they really need to be changed.