How long can you go without replacing the original spark plugs?

I have a Honda with 100k miles. Can I go 200k miles or 300k miles on original spark plugs?

You can, it you don't like good power or decent MPG.

No you'll end up frying a coil. Put a set of NGK or Denso Iridium plugs in.
You should also be getting the valves adjusted every 60,000 miles since all motors made by Honda have a common issue with the valves getting tight.

Quote: "Can I go 200k miles or 300k miles on original spark plugs?"

NO. The electrodes wear down, even if they remain clean.

If you wait long enough, your engine will start to run rough, or maybe not at all. But why do that? Even expensive spark plugs are less than $10, and you can change them yourself (with the right tool).

100k is about the limit.

On the old style spark plugs that had the hook electrode underneath about 60K is the max. I know that because my dad had a VW air-cooled van so it is hard to get at the spark-plugs without the proper spark plug socket(with the rubber insert so you lose the plug in-between the cooling shielding and are feeling in there with your fingers. So I did not do them until I noticed that the van was getting harder to start so it HAD to be done. On my own car I would change them once or more a year.(12K). It is a minor cost and the fuel savings and the performance gain makes it worth it and the faster starting(so less stress on starter motor and on battery and on alternator. It is a WIN in so many areas.

"I HAVE AN ORIGINAL HONDA" WTF do you mean? 1973? When they were first Introduced to the US( or earlier?)
Honda cars has been around since 1963.

Why ask me?

I'm on my third set at 177k, which is about where I'd expect to be.

You can probably go longer. But, I'd change them pretty soon. If you want them to last longer use iridium plugs. They cost more but last a lot longer.

Possibly, but for maximum performance you should change them at 100,000 miles or sooner if necessary.

  • Spark plugs covered with oil plus exhaust smoke? Just got the carbs cleaned and working perfectly on my 82 Honda Nighthawk 450. I started the bike and just a moment later there's a white smoke coming from the engine and exhaust. I took the spark plugs off to aid in addressing the issue and I have found that there's a black oil on them. Anybody have an idea as to what's going on here?
  • Can a motorcycle key be remade without the original? I own a 1975 Honda CB 125s and I lost my key. As I only had one, there's no other key that the new can be based off of. I do have a few places I'm looking for the old key, but figured I'd prepare for the worst.
  • How to read spark plugs over time? I know how to read spark plugs but over time, would a reading be accurate? Have a Honda whose spark plug is maybe 2 years old, would its reading still be similarly accurate as if it was only after a first good week of use? Stock everything, the porcelain is black, I'm upjetting now with a aftermarket exhaust and filter, should I upjet with if the porcelain is black? With the length of time? Should I try a new reading with a new plug? (Already installed one)
  • How long can you drive a Honda Fit continuosly (without stopping except for refuelling for a minute) I have a 2013 Honda Fit 1.3 L with 50k miles on its clock. So far, it still runs smooth like new. How long can I drive it continuosly until it overheats?