How long spark plugs good for?

[Poot]

Hey all,

just have been wondering how long a set of spark plugs might be good for.....

I've got a set of iridium ones in now...so those should also last longer too, no?


just wondering.




POOT

[Mysuzyq]

I have a set of Denso Iridiums in at the moment too....supposedly, they last at least twice as long as conventional plugs. In my experience, even the regular NGK plugs seem to last way longer than the manual recommends, if the bike is tuned properly, but they are cheap to replace, so no reason not to throw in a fresh set every season or two, as recommended.
Tony.

[Speedo]

Plugs are cheap and easy to change. Check often (at least once a season, but more is better). Regardless of miles you ride a season, I like changing at least every 2 years. But yeah, on a good running bike, no reason plugs shouldn't last 10K-20K miles with no problems.

Just so you know, you can ruin a brand new set or older perfectly good older set of plugs in half a heartbeat if your bike has problems. Examples that would cause this would be a no spark/week spark condition in one or more cylinders and various carburation issues such as too rich, too lean.

I don't know what bike you have, but let's assume a 4 cylinder to make my point, which is that its also good to remember that with our older bikes, each cylinder is, in effect, its own little motor and has a separate carb, coil (well, shares with one other cylinder), points/ignition trigger (shares with one other), plug wire, intake boot, and/or possibly air filter of its own (if you run pods). So point is that one plug can go bad due a problem while other 3 stay good.

Hope this helps you.

[doctorgonzo]

I change mine every year (3000 to 4000 miles), they are probably good for 3 or 4 times that long but for $10 why not.

[Steve]

We have only had one GS in the family long enough to change the plugs on it. My wife's 850L was treated to a new set of plugs last year, and I thought they looked good enough to put back in and run some more. Since I had them out, I went ahead and splurged, I put in a new set.

Some of you have seen this picture before, but one of the plugs just came out of my wife's bike with almost 20,000 miles on it, the other came from TheCafeKid's bike with about 5,000 on it.




Now, on my Wing, that's another story altogether.

It thrives on the best neglect I can throw its way.

I did not get any pictures of the plugs I took out, but let's just say that they were not due for replacement either, based on appearance.
I don't know how many miles the previous owner put on them, but I added about 55,000 miles to that count and they still looked good. Not new, but good.

.

[tone]

This is one of those "how long is a peice of string" type questions spark plugs can be duff when brand new out of the box, this is not so common nowdays but used to be a fact of life not so long ago, the only real answer anyone can give is they are good as long as they spark & after that they are scrap

tone