Hey guys,

I don't have my manual by me but wondering how often Harley recommends to change the plugs on the EVO's?

 

At a few bucks each, I change them when I feel like it.

 

Harley manual says inspect every 5k and replace every 10k.

 

Use Iridium plugs and change them every 100K

Stock plugs you might wanna change every 10K

 

Sounds good! Thank You!

 

Do the iridium plugs really go for 100k?

 

Why wouldn`t standard plugs go for a lot more than 10K using fuel injection and an ECM?

 

They do. I haven't bought spark plugs in years. Unless they do not fire, I haven't seen a reason to replace them. Clean and regap, reinstall ,start and ride. Heck plugs in your car will go 100,000 miles ,why do bike plugs only last 10k?. So that Harley can sell more uneeded parts for the profit.,,

 

Not quite true...once the centre electrode has lost its square profile you are losing efficiency and that can lead to misfires and fouling. Iridium plugs don't erode the electrodes very much, if at all and that is why they last so long.

Also remember that on a single fire system the plugs fire twice as often as a car in a harsher environment.

 

I'll tell you in another 70K....they can go a lot more than that in a car. Nissan fit Iridiums to the VQ series V6 motors because its a 3 hour job to change the plugs....some VQ's go their entire life without a plug change.