Spark Plugs

[flynrider]

I'm not able to find LMAR8A-9S in Singapore.
Some web site seems to suggest NGK Standard Plug DR9EA and Iridium Plug DR9EIX plugs are compatible.
Any advise?
Thanks in advance.

Chung

Just looking at product photos, it doesn't look like the DR9EA is compatible. It is a standard style plug. The NGK LMAR8A-9S has a much longer nose.

i checked a few spark plug cross-reference sites and they only list a Honda part #, which is likely just Honda's number for the NGK plug.

Honda 31908-MGC-A0000
Honda 31908-MGC-0031
Honda 31908-MGC-003

 

[Stealth128_imp]

Ouch lot of money but lota plug.What else does this plug fit?

 

[Pterodactyl_imp]

Maybe the NKGs will last longer than the service replacement schedule suggests. My bike is now just under 38000kms and I pulled the plugs to check them only last week. No wear visible on the electrodes, colour good (light tan), and gap as specified at 35 thou. Didn't even have to pull out the wire brush.The 38000kms service schedule suggests replacement. Why?

Cheers

During my diagnostic battle with my TSR Header, (she has no go now between 5K and redline, I suspect the PC V is dumping too much fuel) I pulled the plugs to see how she was running (they look on the rich side to me) The threaded portion of the plug is an inch long!

Just a word of advice guys, If you haven't pulled your plugs yet, do it and give them a good coat of anti-seize. The plugs take a 14 mm socket. Cheap insurance

(my bold)

Sounds like good advice. Although Honda do not regard that as a lubrication point.

 

[the Ferret]

Ptero...that's like 24,000 miles isn't it? Doesn't Honda call for replacement at 8,000 miles (13,000 kms) or is that just an inspection?

 

[Cormanus]

My manual says inspect at 12,000 kms (7,500 miles), replace at 24,000 kms (15,000 miles), inspect at 36,000 kms. It gives up then.

 

[Pterodactyl_imp]

Ptero...that's like 24,000 miles isn't it? Doesn't Honda call for replacement at 8,000 miles (13,000 kms) or is that just an inspection?

My manual says inspect at 12,000 kms (7,500 miles), replace at 24,000 kms (15,000 miles), inspect at 36,000 kms. It gives up then.

Guys I didn't make myself clear. Honda did the 12000 and 24000 (km) services and changed, and charged for, the plugs. The bike was under warranty. My bike is now at 38000kms. However, if those NKGs can only handle 12000kms, or even 24000kms, then I'll be one of those ring-tailed whatchamacallits. After 16000kms since being changed, the electrodes are not worn, the insulators are intact and not discoloured, the gaps are still perfect and the colour of all plugs is good. Why change? I will have another look in another 6000kms but, even then, unless these plugs are not built to last, I would expect to see considerable life still left in them.

My experience with plugs tells me that if the electrodes are in good condition and the insulators are not cracked (normally by heavy handed changing, but also by heat) then the plug is as good as new. A good quality plug (platinum) should last anywhere between 30000 to 60000 miles and iridiums up to 120000 miles. High performance (revving) motorcycle motors and heat intense motors (as in air cooled maybe) may reduce the life of platinum plugs to maybe 20000 miles. Race bikes, for obvious reasons, to much less. But the CB hardly fits into those categories. As for heat control, I guess that is one reason that Honda oil cooled the galleries adjacent to the plugs. Plug wear should first become apparent by the rounding off and then erosion of the tip of the centre electrode. I don't see any evidence of that on my 12000kms old plugs. Polish them up, wrap them in tissue, put them in a box and you could sell them as new.

However, maybe I am being pennywise and pound foolish. Maybe not built to last is a factor. But I think NKG would dispute that. The Honda service manager might have a different view. Ferret, you have done a lot of miles in modern bikes, have you ever had a plug breakdown? Anyone else? Tell me what you think?

Cheers

 

[the Ferret]

I have never had a plug break down and misfire. I replaced the plugs in my ST at 25,000 miles but the plugs that came out looked just like the plugs that went in. Many on the ST board run them 50,000 or more.

I suspect I will inspect the ones in my CB at about 20,000 miles, unless it starts misfiring, or gets hard to start, or my gas mileage drops off.

 

[redbirds_imp]

Ptero...that's like 24,000 miles isn't it? Doesn't Honda call for replacement at 8,000 miles (13,000 kms) or is that just an inspection?

My manual says inspect at 12,000 kms (7,500 miles), replace at 24,000 kms (15,000 miles), inspect at 36,000 kms. It gives up then.

Guys I didn't make myself clear. Honda did the 12000 and 24000 (km) services and changed, and charged for, the plugs. The bike was under warranty. My bike is now at 38000kms. However, if those NKGs can only handle 12000kms, or even 24000kms, then I'll be one of those ring-tailed whatchamacallits. After 16000kms since being changed, the electrodes are not worn, the insulators are intact and not discoloured, the gaps are still perfect and the colour of all plugs is good. Why change? I will have another look in another 6000kms but, even then, unless these plugs are not built to last, I would expect to see considerable life still left in them.

My experience with plugs tells me that if the electrodes are in good condition and the insulators are not cracked (normally by heavy handed changing, but also by heat) then the plug is as good as new. A good quality plug (platinum) should last anywhere between 30000 to 60000 miles and iridiums up to 120000 miles. High performance (revving) motorcycle motors and heat intense motors (as in air cooled maybe) may reduce the life of platinum plugs to maybe 20000 miles. Race bikes, for obvious reasons, to much less. But the CB hardly fits into those categories. As for heat control, I guess that is one reason that Honda oil cooled the galleries adjacent to the plugs. Plug wear should first become apparent by the rounding off and then erosion of the tip of the centre electrode. I don't see any evidence of that on my 12000kms old plugs. Polish them up, wrap them in tissue, put them in a box and you could sell them as new.

However, maybe I am being pennywise and pound foolish. Maybe not built to last is a factor. But I think NKG would dispute that. The Honda service manager might have a different view. Ferret, you have done a lot of miles in modern bikes, have you ever had a plug breakdown? Anyone else? Tell me what you think?

Cheers

My manual says inspect at 12,000 kms (7,500 miles), replace at 24,000 kms (15,000 miles), inspect at 36,000 kms. It gives up then.

Guys I didn't make myself clear. Honda did the 12000 and 24000 (km) services and changed, and charged for, the plugs. The bike was under warranty. My bike is now at 38000kms. However, if those NKGs can only handle 12000kms, or even 24000kms, then I'll be one of those ring-tailed whatchamacallits. After 16000kms since being changed, the electrodes are not worn, the insulators are intact and not discoloured, the gaps are still perfect and the colour of all plugs is good. Why change? I will have another look in another 6000kms but, even then, unless these plugs are not built to last, I would expect to see considerable life still left in them.

My experience with plugs tells me that if the electrodes are in good condition and the insulators are not cracked (normally by heavy handed changing, but also by heat) then the plug is as good as new. A good quality plug (platinum) should last anywhere between 30000 to 60000 miles and iridiums up to 120000 miles. High performance (revving) motorcycle motors and heat intense motors (as in air cooled maybe) may reduce the life of platinum plugs to maybe 20000 miles. Race bikes, for obvious reasons, to much less. But the CB hardly fits into those categories. As for heat control, I guess that is one reason that Honda oil cooled the galleries adjacent to the plugs. Plug wear should first become apparent by the rounding off and then erosion of the tip of the centre electrode. I don't see any evidence of that on my 12000kms old plugs. Polish them up, wrap them in tissue, put them in a box and you could sell them as new.

However, maybe I am being pennywise and pound foolish. Maybe not built to last is a factor. But I think NKG would dispute that. The Honda service manager might have a different view. Ferret, you have done a lot of miles in modern bikes, have you ever had a plug breakdown? Anyone else? Tell me what you think?

Cheers
Same here. As example, My Jeep Liberty came with conventional spark plugs, non-platinum, yet did not need replacement until about 70,000 miles when I replaced them with platinums. I'll check the plugs on my CB at regular intervals but will only replace them when they show wear on the electrodes.

 

[the Ferret]

In the old days ( the 70s lol) when you had points, condensers and coils, sometimes the spark was weak and plugs had trouble firing properly causing them to wear. These days with electronic ign and FI that automatically provides an awesome spark everytime and the correct air fuel ratio at all times, I think plugs have a pretty easy job of it.

 

[ClassicVW_imp]

I agree. And I think they should be able to last a lot longer than the change interval listed. If my lowly Toyotas can have 100K mile plugs, why not a premium Honda motorcycle?!

 

[Pterodactyl_imp]

Ptero...that's like 24,000 miles isn't it? Doesn't Honda call for replacement at 8,000 miles (13,000 kms) or is that just an inspection?

My manual says inspect at 12,000 kms (7,500 miles), replace at 24,000 kms (15,000 miles), inspect at 36,000 kms. It gives up then.

Further to my last:

I wasn't avoiding your questions regarding plug change intervals, just making sure my facts were right. In fact you are both right.

Firstly the Honda Shop Manual calls for plug REPLACEMENT at 8000miles and every 8000 thereafter. Inspection is at the 4000 mile intermediate services. This equates, to us tied to a metric system, to 12.8 thousand kilometres and every 12.8 thereafter for REPLACEMENT. Inspections at the 6.4k intermediate services.

The Honda Owners Manual calls for REPLACEMENT at 24000 kilometres and every 24000kms thereafter. Inspections at the 12000kms intervals.

Quite a disparity, to say the least. It's true that my shop manual is for the 2013 model but let's face it, a spark plug is a spark plug when its the same plug for the '10 through '13 models (NKG LMAR8A-9S).

The Honda dealer's service manager, mine anyway, likes to follow the shop manual intervals. Keeps the stock turning over I guess. I would have one message for him:

Cheers

 

[Cormanus]

Love The Castle.
By the way, my plugs got replaced at about 15,000 kms as my 12,000 km service was delayed while I rode about the place with Pterodactyl. The mechanic told me the ones he replaced looked pretty good. He wasn't sure why he replaced them. They were very expensive too.

 

[furious_blue_imp]

I agree. And I think they should be able to last a lot longer than the change interval listed. If my lowly Toyotas can have 100K mile plugs, why not a premium Honda motorcycle?!

my guess: typical car engines probably run at lower rpms than motorcycles. That means the the plugs in the car fire less often per mile so that might mean that they last for 'more miles' for the same number of times being fired.

 

[Pterodactyl_imp]

I agree. And I think they should be able to last a lot longer than the change interval listed. If my lowly Toyotas can have 100K mile plugs, why not a premium Honda motorcycle?!

my guess: typical car engines probably run at lower rpms than motorcycles. That means the the plugs in the car fire less often per mile so that might mean that they last for 'more miles' for the same number of times being fired.

my guess: typical car engines probably run at lower rpms than motorcycles. That means the the plugs in the car fire less often per mile so that might mean that they last for 'more miles' for the same number of times being fired.
You are right. See post #26

Quote:My experience with plugs tells me that if the electrodes are in good condition and the insulators are not cracked (normally by heavy handed changing, but also by heat) then the plug is as good as new. A good quality plug (platinum) should last anywhere between 30000 to 60000 miles and iridiums up to 120000 miles. High performance (revving) motorcycle motors and heat intense motors (as in air cooled maybe) may reduce the life of platinum plugs to maybe 20000 miles. Race bikes, for obvious reasons, to much less. But the CB hardly fits into those categories. As for heat control, I guess that is one reason that Honda oil cooled the galleries adjacent to the plugs. Plug wear should first become apparent by the rounding off and then erosion of the tip of the centre electrode. I don't see any evidence of that on my 12000kms old plugs. Polish them up, wrap them in tissue, put them in a box and you could sell them as new.
Cheers

 

[flynrider]

I have never had a plug break down and misfire. I replaced the plugs in my ST at 25,000 miles but the plugs that came out looked just like the plugs that went in. Many on the ST board run them 50,000 or more.

I suspect I will inspect the ones in my CB at about 20,000 miles, unless it starts misfiring, or gets hard to start, or my gas mileage drops off.

This is what I've always done. I pull 'em every few years to clean and gap, then put 'em right back in.

The CB750's stock plugs went 25K miles. The electrodes still looked fine, but one of the plugs developed a hairline crack in the ceramic and started to misfire.

 

[linuxology_imp]

sorry to necrothread, but what are the gap specs on the plugs?

 

[the Ferret]

I think .031. Popgun verify? I am putting in my set on Tuesday at 26,000 miles. Will try and do a pic tute.

 

[Lord Popgun]

And the manual says: 0.80-0.90mm (0.031-0.035 in)

 

[the Ferret]

Why do they give you a range. Why not .033 or something? I hate making decisions lol

 

[Lord Popgun]

LOL Hey, I just quote the manual, not write it...