Spark plugs

[Mallett]

What is the recommended mileage to change spark plugs?...

[Bone]

The Service manual has us changing them every 8k miles.

I check and gap them every year then at 60k felt like I should change them and did.

You have to decide what's best they last a long time.

[salty1]

Every 8000 miles as posted by Bone. They are inexpensive and it's an easy R&R. Honda had a reason for this schedule. FWIW.

[pancho]

Pull them all out to evaluate their wear and temperature/color, and see the general operating condition of your motor. If they look good and are burning properly, put them back in for another season.

[Hoser]

I've changed them once, that was about 50,000 miles ago.  I  Look at them and check the gap once in a while.
Hoser  

[Former BMW Guy]

Pull them all out to evaluate their wear and temperature/color, and see the general operating condition of your motor. If they look good and are burning properly, put them back in for another season.

I agree.
And I always throw a spare in my tank bag....just in case.

JP

[Valker]

To each his own. I changed mine at 50,000 and they looked new so I kept the old ones in a box. I now have 86,000 on those plugs, and they still look new. I'll just leave them.

[gordonv]

I always keep an eye on my MPG, and I have NEVER noticed any improvement after changing them at the manufacturers recommended mileage.

At $2-3 each, I went to Iridum plugs for only $7 instead, and they are rated at 100K miles. I figure they will last me a life time before needing to be changed.

[Rio Wil]

This plug is representative of one of six I pulled out at 100K miles. Note the center electrode is still quite square and the gap on all plugs had increased from .032 to .035.  Don't waste your money on 8K changes......like some have said, check them for color and gap at 50K intervals and forget them. After replacing mine at 100K, there was no difference, same 32-40 mpg, same silky smooth idle, same great acceleration.....nothing changed....use stock auto plugs at couple of bucks each....next change is at 200K  (178K now)
 

[Chiefy]

I changed mine when I bought the bike and 10k miles later.  Cheap and easy, and I know the engineers at Honda know more about it then me.

[john]

           |"  has us changing them every 8k miles "                               

[Rio Wil]

and I know the engineers at Honda know more about it then me.

Suspect that might be true....

[RP#62]

If it were just the engineers that determined such things, that would be one thing, but its the engineers, the lawyers, the marketing people etc that determine what goes in the books.  Use the book as a starting point and then modify based on your own experience.
-RP

[Chrisj CMA]

buy your spark plugs at car parts places.  Half the price for the exact NGK part.  Change it whenever you want, I think after every ride would be neat because you would always have new plugs.

(Just kidding) Unless you have modified your motor...if you have I have no comment YMMV, If you havent, spark plugs in Valkyries last a long time.  Change at 50K is very reasonable.

Or you can believe theres something magic about the expensive ones at the Honda Dealer and change them every 8K like the book says.  I wont make fun of you ......................................... (much)

[Chiefy]

and I know the engineers at Honda know more about it then me.

Suspect that might be true....

LOL.  I've worked on business machines for years.  Over the years my co-workers and I have had times where we laughed off something that the designing engineer built or said.  Have met a few of them over the years.  I was always amazed at the well thought out reasons they gave when I asked why they built something (that we laughed at.)  And as to why it wasn't obvious to myself or my co-workers.  Yeah, I fed you a softball with that reflection.  Swing away I guess.

Personally, I would love to ask the designer why he recommends 8k miles.  Figure I would probably learn something.

[Patrick]

I like to look at them every now again before they 'glue' themselves in. Its not so much as to look at the sparklers themselves as it is to make sure the drain hole is clear, stick a feeler gauge in them and add some anti-seize to them.

[Mallett]

I like to look at them every now again before they 'glue' themselves in. Its not so much as to look at the sparklers themselves as it is to make sure the drain hole is clear, stick a feeler gauge in them and add some anti-seize to them.

+1 Patrick

[Chrisj CMA]

I like to look at them every now again before they 'glue' themselves in. Its not so much as to look at the sparklers themselves as it is to make sure the drain hole is clear, stick a feeler gauge in them and add some anti-seize to them.

I look every once in a while, but I never worry about them gluing themselves in.  A dab of anti seize works wonders, work it around deep in the threads all around and they go in and out like butter

[Tropic traveler]

Never paid much attention to plug change intervals. Previous owner {according to detailed records} put new ones in at 38,000. I put new ones in at 78,000 due to a hydrolock, just put in a fresh set of NGK's at 115,000. Does "seem" to idle a bit smoother but other than that not much. Paid $16 for the set of 6 a my local Carquest.
Patrick is spot on about checking the drainholes, good call!

[blastedbugler]

I cant get over how in the USA parts are so cheap.
GordonV says that normal plugs cost $2-$3 while Iridium cost $7.
In Aussie normal plugs are $12 & Iridium about $25-$30.
I run Iridium in all my bikes as they give far better & longer performance, especially in my vintage Adler 2 stroke.
Iridium however are a no no in magneto powered bikes because they have a inbuilt resistor.
Don ( Aussie )

[Fritz The Cat]

I changed mine when I bought the bike and 10k miles later.  Cheap and easy, and I know the engineers at Honda know more about it then me.

Yep, and the marketing people know how to relieve you of your money.