Spark Plug
Seasoned HDF Member
Joined: Dec 2010
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From: Coromandel Peninsula New Zealand
Stock plugs you might wanna change every 10K
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From: Newcastle, OK
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From: Deep in the heart of New Jersey
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.,,
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Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
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.
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
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.