Question Removing spark plugs for valve adjustment?

[16DCT]

It's time for a valve adjustment/check on my 2016 NC700X D.

Do you typically remove the spark plugs for this job or do you leave them in?

 

[670cc]

I do not remove the spark plugs.

I think technically the compressible gasket on the spark plug is designed for one time use, but that is debatable. Regardless, I do the valve adjustment just fine without removing the plugs, so I see no point doing the extra work of removing and reinstalling them.

The plugs last a long time. I think mine have been removed and inspected once in 57,000 miles.

 

[16DCT]

I do not remove the spark plugs.

I think technically the compressible gasket on the spark plug is designed for one time use, but that is debatable. Regardless, I do the valve adjustment just fine without removing the plugs, so I see no point doing the extra work of removing and reinstalling them.

The plugs last a long time. I think mine have been removed and inspected once in 57,000 miles.

Ah, that's good to know. Funny enough I just hit 57,000 miles last night, but I haven't checked on the condition of the spark plugs yet.

 

[potter0o]

+1 for what 670cc said

 

[dduelin]

I pull the plugs & inspect if only for fear of the steel plugs seizing in the aluminum cylinder head. Admittedly that hasn’t happened on any Honda I have owned and only once in my 50 years of fiddling with machinery.

 

[bigbird]

I leave the plugs in.

 

[Doc True]

Is there a replacement interval for spark plugs or is it an inspection and replace if needed?

 

[670cc]

O

Is there a replacement interval for spark plugs or is it an inspection and replace if needed?

The owner’s manual (my 2012) maintenance schedule recommends spark plug inspection every 16,000 miles / 25,600 km, and plug replacement every 32,000 miles / 51,200 km.

That is the recommendation. I do not follow it. I have proven to myself that the NC’s spark plug longevity is ample enough to not warrant such frequent spark plug maintenance tasks.

 

[Deleted member 1183]

I pull the plugs & inspect if only for fear of the steel plugs seizing in the aluminum cylinder head. Admittedly that hasn’t happened on any Honda I have owned and only once in my 50 years of fiddling with machinery.

Same here plus the aspect that it is easier to turn the crank without compression.

 

[itsmenc700]

Why do bike makers state such short change intervals for plugs.
The last few cars I've had have said to replace the plugs at 100,000 miles.
But my bike needs new ones at 30,000 miles - why??

 

[dduelin]

The electrode does erode over time of use and since motorcycle engines in general may operate at rpms 2 to 4 times higher than a car engine that is why MC spark plugs do not last as long. Another reason is many motorcycles use a "wasted spark" electrical system where the plug fires twice as often as the cylinder actually requires it. Cars are usually more sophisticated and only fire the individual spark plugs when required.

The plugs in the NC have twice the replacement interval of other motorcycles I have owned I guess because they have iridium electrodes but they are crazy expensive and don't make up for the extra mileage interval.

 

[itsmenc700]

BUT Iridium is to be a better longer lasting metal used in plugs, so.....

 

[670cc]

Why do bike makers state such short change intervals for plugs.
The last few cars I've had have said to replace the plugs at 100,000 miles.
But my bike needs new ones at 30,000 miles - why??

Honda is specifying the same spark plug replacement interval for the NC’s partial iridium plugs as they are for my ‘02 Goldwings copper plugs. I think it may just be their habit and/or standardization of maintenance intervals.

To your point about cars. Yes, I replaced my car plugs at 100,000 miles. It runs a little lower RPM than the NC, but not a big difference. I think Honda’s motorcycle replacement interval is too frequent, as I suggested earlier, my own experience is that the spark plugs in the NC appear to be fine for double the time Honda suggests. To each his/her own. There is no right or wrong, just more hassle or less hassle, whichever you prefer.

By the way, if an owner wanted to save money on plugs, and wants to do the replacements at 32,000 miles, we established on the forum long ago, through a reputable source, that the Goldwing 1832cc engine plugs are usable in the NC, and cost much less than the iridium plugs.

 

[dduelin]

Honda is specifying the same spark plug replacement interval for the NC’s partial iridium plugs as they are for my ‘02 Goldwings copper plugs. I think it may just be their habit and/or standardization of maintenance intervals.

To your point about cars. Yes, I replaced my car plugs at 100,000 miles. It runs a little lower RPM than the NC, but not a big difference. I think Honda’s motorcycle replacement interval is too frequent, as I suggested earlier, my own experience is that the spark plugs in the NC appear to be fine for double the time Honda suggests. To each his/her own. There is no right or wrong, just more hassle or less hassle, whichever you prefer.

By the way, if an owner wanted to save money on plugs, and wants to do the replacements at 32,000 miles, we established on the forum long ago, through a reputable source, that the Goldwing 1832cc engine plugs are usable in the NC, and cost much less than the iridium plugs.

The Goldwing spark plug replacement, at least my '08, is at 16,000 miles. The NC is 32,000 miles.

 

[bigbird]

By the way, if an owner wanted to save money on plugs, and wants to do the replacements at 32,000 miles, we established on the forum long ago, through a reputable source, that the Goldwing 1832cc engine plugs are usable in the NC, and cost much less than the iridium plugs.

If the Goldwing plugs are the exact match to the NC's Iridium plugs, then why wouldn't Honda spec the Goldwing plugs for the NC in the first place?
There must be a legitimate reason if the size, gap, and heat range are identical.
Personally I wouldn't do it.

 

[670cc]

I

The Goldwing spark plug replacement, at least my '08, is at 16,000 miles. The NC is 32,000 miles.

Thanks for setting me straight. I looked it up and you are correct. I guess I said 32,000 mile Goldwing (1832cc) plug replacements earlier because I chose to double the Goldwing’s interval, just as I have with the NC.

Only 16,000 miles for spark plugs? That is nuts.

 

[670cc]

If the Goldwing plugs are the exact match to the NC's Iridium plugs, then why wouldn't Honda spec the Goldwing plugs for the NC in the first place?
There must be a legitimate reason if the size, gap, and heat range are identical.
Personally I wouldn't do it.

I don’t know. I just heard that it works and has been done. I think the old posts about it have disappeared with forum software changes.

 

[brb]

I do the valve adj. coolant flush and check the plugs every other year on my 2012 since new about 9K. Replaced the plugs at 32K even thou the plugs looked great it is there replacement int. per Honda. The spark of any plug will start at the sharp edge of the ground or center electrode. Looking at the edges of mine the slight rounding(looking with a 10X magnifier) It was hard to replace them when I knew they will last a lot longer but I did. Older conventional spark plugs would wear (increased gap) when you had higher milage 30~50K(every spark is a little lightning bolt that erodes the metal). When that happens the coils need a higher voltage to jump that higher gap and when you have a higher voltage the duration (burn time) is shorter. When MFGs started using platinum it allowed 60K interval changes without that increased gap. Coils running higher voltages to jump bigger/rounder gaps and will not last as long. That is why I changed at 32k with the hope that the coils will last longer and the duration of the spark will insure proper combustion.

 

[showkey]

That is why I changed at 32k with the hope that the coils will last longer and the duration of the spark will insure proper combustion.

Not sure that theory has merit because even with old bikes with electronic ignition:

Older bikes gapped at .6-.7mm. Conventional electrode material
new bikes like the NC gap at 1.0mm to 1.1mm with iridium material

The new bike gapping is 30-40% larger with no noticeable change in coil life and a vast increase in mileage interval.

The there’s the coil(s) itself that last +100,000- 300,000 miles with no service interval on the auto side.

 

[brb]

Was just adding my 2cents about spark plug replacement in general for bikes and cars. What i was sharing was what Honda trained in the 80s and what ASE has supported. I replaced many coils in my life working as a Auto/Motor mech. and when you see the under maintained condition of the plugs of those engines the theory does have merit. When my older brother and his buddies were hopping up there cars in the 70s a Boss 302 was having a ignition problem and the talk was that the .035 gap was getting snuffed out. He started gapping at .028 and the problem went away. In the 90s when I was doing emission failure on cars depending on the failure we would Scope the ignition system and check Kv voltage and burn time. When seeing .4 m/sec burn time and higher Kv it would point to a lean condition or higher gap. Seeing a 2.5 m/sec burn time and lower Kv a rich condition was happening most likely. From what some of the Experts would teach was that the gap was important for the kernal size of the ignition. That Boss 302 was not checked with a scope but the smaller gap worked, was there enough dwell time was the coil breaking down? Who knows what I can say is any ignition system can work outsize of its design/ maintenance but when it fails the engine does not run.