Spark Plugs

[Firefighter]

How far do you guys go on a set of spark plugs? Mine look new at the 8000 mile point. There cheap, but should they be replaced that soon? Thanks

[sandy]

I think I've gone 30,000 on a set without problems.

[The emperor has no clothes]

I've got 60k on the originals.

[RonW]

I put 6 new plugs, and it didn't make a difference at all. I think its more important to remove the spark plugs every so often so the threads don't gall then screw them back in. There was an article about not using anti-seize on the threads. I can't find the article but the reason was that the spark plug threads have some sort of coating that reacts badly to anti-seize.

[NEHI]

   77k on my originals and they still look ok.

[Chrisj CMA]

50k is a good number to me.  May still not be necessary, but by then you don't feel like you are wasting money.

[Savago]

Dear friend

Before changing the spark plugs, my I/S was doing 29-31mpg at highway speeds (65-70 mile/hour). After I changed them, it is now making 33-36 mpg. That is at least 12% improvement.

Since the spark plugs are so cheap (USD 2.09 plus free shipping @amazon), I would change them from time to time, even if they still look good.

Cheers


Savago

[Firefighter]

Thanks for all the replies, never heard about the anti seize part as I have that stuff everywhere. I do not see any rounded or burning of the electrode at all.

[Jess from VA]

All my plugs forever have (a dab, not a gob of) copper antiseize, and I have only good results.

[Rio Wil]

I replaced the original set at 100K miles and the second set has 120K........bike is easy on plugs.....maybe I will change them out of guilt.... ....used a little nickle never seize on the second set. New plugs make no difference in performance .....unless you got some issues with carbs, seals, etc. and they foul

[gordonv]

I used to change my plugs in my vehicles, but I never got a different MPG out of it. So I have decided it is a waste of time, UNLESS I get different mileage.

I've heard to use copper antiseize. I would recommend to take them out for inspection and to insure they aren't seizing in the block. Sparks like sharp corners, so I would file the electrode a little and check the gape.

So I don't have to do this, I'm installing Iridium plugs in my GL1500 next year. Good for 100K miles, and only 3x the $. This is after 2 years of driving to insure my MPG is stable, as I've been doing other maintenance on the bike first (filters, synthetic oil, new tires [CT]).

[RonW]

..... never heard about the anti seize part as I have that stuff everywhere.

I ran a search the Internet and came up with the following reasons why anti-seize shouldn't be used on the threads of a spark plug.

• NGK plugs have a trivalent plating (the silver or chrome color) which acts as a release agent by preventing corrosion from moisture and chemicals. I guess the trivalent coating also prevents galling from electrolysis (dis-similar metals). Other brand plugs may have similar coatings.

The rest of the negative aspects are more like precautions since the negative aspects can be worked around.

• anti-seize throws off the torque value for a given bolt. That's common knowledge and who uses a torque wrench on a spark plug. Nevertheless this is the primary reason spark plug manufacturers have issued their bulletin.

• if anti-seize is non-conductive, it'll affect the ground return path of the plug through the cylinder head. I guess that's not a problem if copper anti-seize is used.

• anti-seize tends to isolate heat into the spark plug. This disadvantage can be ignored since the spark plugs on a Valk seem to last forever even on those with anti-seize on their threads.

[98valk]

All my plugs forever have (a dab, not a gob of) copper antiseize, and I have only good results.

never use copper anti-sieze on spark plugs. galvanic corrosion can start. copper helps to make a little battery. always use silver anti-sieze.

[98valk]

How far do you guys go on a set of spark plugs? Mine look new at the 8000 mile point. There cheap, but should they be replaced that soon? Thanks

only way to know is take an ohm reading of new plugs, install, run, and check at OEM change recommendation. if ohm reading still the same or within spec continue to use, however make sure all of the edges are sharp and not rounded. use an eye piece to inspect. the internals can wear out even though the external still looks good.  remember drag racers tend to change plugs after each run. they have found HP loss even after one run on the plugs.
see my post about the plugs I use and how to modify
 http://www.valkyrieforum.com/bbs/index.php/topic,8041.0.html

[Jess from VA]

All my plugs forever have (a dab, not a gob of) copper antiseize, and I have only good results.

never use copper anti-sieze on spark plugs. galvanic corrosion can start. copper helps to make a little battery. always use silver anti-sieze.

Now you tell me.   

[Pappy!]

It is not just copper although it is one of the worst offenders. Any metal more noble than aluminum will force the aluminum to be sacrificial to it. Look up a metal Nobility scale.
The issue is enhanced since the anti-seize is more or less a liquid and provides a ton of contact surface.

For those in doubt just look up 'Galvanic Corrosion' to see why this happens.

In general most spark plugs are plated in the threaded area. The plating itself acts as a lubricant of sorts.