2005 & up you should stay with stock H-D plugs check other treads on this subject it has to do with the electronic ignition problems when running other than a stock plug or check with the stealer.

 

I pulled mine at 30,000 they looked good so put them back in, i have 41,000 still runs good.

 

how often do you change your cars? why would the bikes go bad

 

With modern days ignition system plugs can go long way and just use stock anything else won't make a dent in performance life or whatever expected of em.

 

I changed mine at 27,000 and they still looked great.

 

Thanks for all of the real proven facts on my subject; you guys really help me out when I ask.

 

I have right at 28k and the original plugs still look new. I got 48mpg on a 3000 mile round trip two up with a mountain of luggage stacked high on the tourpak two weeks ago. Ill change them when they actually start showing some signs of wear.

 

...replaced mine with OEM plugs at 10K. However the old ones looked like they could go anouther 10K miles. I always stay with OEM parts in all my vehicles and motorcycles as much as I can.?

 

I use Screaming Eagle triple platinum...not sure if it really helps but left them in there for 30000 miles and they looked a bit nasty...bought another set for $15 put them in at about 40000 i think...I still have the old ones as spares because they look good...I am gonna leave these in for a long time.

 

I change my plugs around 10K or once per year. I think it is just a good thing to do, they are fairly inexpensive, and keeps the bike running in top condition.

I use NGK Iridium: DCPR7EIX. Great plug.