Spark Plug Life......

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olChris

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Why is it that we can have a spark plug into a modern vehicle and it can do 10-20k kilometers with thousands of startups and not have a problem with them.????

I can put a new NGK plug into my Norton and they seem to fail in a very short time/milage.. I guesstimate several hundred miles over a few (3) month period.. eg start up every other week and do 30 odd miles just to keep things moving...

One of my bikes in particular, Mk3 with original leads, caps/coils and electronic (Boyer) ignition runs perfectly with new plugs for a while.. After about 30 startups (over months) it runs hithouse at warmup/idle.... Cleaning plugs works for a few more startups then fail again...

I think the plugs fail "internally" for some reason. Could this be caused by my "old" coils, boyer, and dodgey old champion plug caps that look fine but not real sure about how good their contact is with plug tip...

Could the old electrical system components, that work great for the best part, overly contribute to the continual spark plug failures that i seem to have...
 
Something is wrong there as I've used the same plugs for years with an occasional cleaning using my old bead blast plug cleaner. I have found the if your mixture is too rich or you're oil fouling the plugs naturally they won't work,but cleaning them brings them back good as new. Are your electrodes eroded?
 
You need to change the brand, or grade, of fuel that you use.

Always buy the same stuff.
Ask what others in your area are successfully using.

I used shell optimax in bikes with carbies for quite a while.
Then they changed the formula... ?

You may also need a one grade warmer plug....
 
There are a lot of counterfeit NGKS and Champion spark plugs being made, and they are so convincing, that they are even getting into batches of plugs being distributed to large reputable motor stores (like Halfords in the UK for example)

The most common place to find counterfeit plugs is at the shows and jumbles.

My Dad and I have had problems with brand new plugs being dud, or breaking down very quickly in several bikes (Norton, Ariel and Sunbeam)

We are trying Bosch plugs at the moment in all bikes, and so far so good... no issues in any of them, good running and good starting.
So far, highly recommended!
 
Rohan said:
You need to change the brand, or grade, of fuel that you use.

Always buy the same stuff.
Ask what others in your area are successfully using.

I used shell optimax in bikes with carbies for quite a while.
Then they changed the formula... ?

You may also need a one grade warmer plug....
Click to expand...

So why does the fuel grade, or why does it contribute to plug failure ????????..... Ive changed plug temp from 6 to 7 back to 6, no difference.
I buy the premium fuel 3x20ltr jerry cans for bikes and several other motors and there fine.. eg 3 B/Stratton mower motors, 3x 2stroke cheapo, blower,c/saw snipper etc.......... Im sure it's not the fuel..
 
phillyskip said:
Something is wrong there as I've used the same plugs for years with an occasional cleaning using my old bead blast plug cleaner. I have found the if your mixture is too rich or you're oil fouling the plugs naturally they won't work,but cleaning them brings them back good as new. Are your electrodes eroded?
Click to expand...

Tried that many a time and starts missing v/quickly (30mins -1hr running).. New plugs then OK... I got over a dozen plug sets in the "bin".. No time to erode..
 
gtiller said:
There are a lot of counterfeit NGKS and Champion spark plugs being made, and they are so convincing, that they are even getting into batches of plugs being distributed to large reputable motor stores (like Halfords in the UK for example)

The most common place to find counterfeit plugs is at the shows and jumbles.

My Dad and I have had problems with brand new plugs being dud, or breaking down very quickly in several bikes (Norton, Ariel and Sunbeam)

We are trying Bosch plugs at the moment in all bikes, and so far so good... no issues in any of them, good running and good starting.
So far, highly recommended!
Click to expand...

Yes.. you may be right with duds.. Within one of my alter egos i had/have 2stroke 1/4 scale remote control stuff... Ngk plugs were the choice and would fail "often".. And at times were a dud out of the box... In saying that i have run NGK in various motors with no problem, but in either of my Nortons there is a problem...
 
olChris said:
Ive changed plug temp from 6 to 7 back to 6, no difference.
Click to expand...

The standard NGK plug for a Commando is BP7ES (= Champion N7Y) . Why are you using ??6??
 
If Stan Is to be believed in his book modern plugs have an overlap in heat range and plug numbers are not as critical as they once were. From memory...........and mine if fading fast.

J
 
The computers on modern cars plus the better ignitions allow plugs to stay in your engine longer. Pull a plug on a newer car at 100,000 miles and you will probably find a gap double the size that it started at. Try NGK iridium plugs, I had good luck with them when I was having the same problems as you.

olChris are you adding anything to you fuel on a normal basis?

Pete
 
I have tried a bunch of different plugs and my bike seems to like Champions the best. Most of my cars do fine with NGKs or Bosch. Since you are replacing plugs every few months, why not try out a few different brands. The most expensive might not run the best for whatever reason.

Greg
 
Just a thought about your fuel, you said you buy jerry cans of it and also only put 30 miles on the bike every other week or so.. If you have the miserable ethonal crap fuel we do here that alone could be your problem. If my BSA sits like that the vented cap allows the ethonal or whatever it is to evaporate over a month or so & starting & preformance are noticeably bad.. Might be part of the equation?
 
Who knows what combo of factors messes with a particular bike's plug life but generally its embeded carbon in surface pores that at some point no amont of solvent cleaning can touch but drive it a bit deeper so more room for more conduction shorting carbon. Mechanics that work on my cars have told me they will no longer install Bocsh plugs as they had too many quick returns d/t missfiring so AC Delco is their pick instead. Its was Champion plugs that taught me after much self brow beating and kicking fatique depression to dig out the crappy old plugs to solve the mystery and never buy Champion again nor other plugs only two new at a time. Until my buddy Wes re-ringed his '71, for a few years it was routine to pull over and watch him whip out jacket pocket tools and clean both plugs while staying on the seat. I've had some intermitent coil connections cause plugs to foul so have burts and shocked my self reaching under on the fly to diagnos or fix for a time. Why do we have to change oil so much more often than modern craft?
 
olChris said:
Cleaning plugs works for a few more startups then fail again...





quote]
I think this is the key. What are you exactly cleaning from the plugs every few hundred mile? Carbon deposits, do to either oil or too rich a mixture will render any plug useless well before it is worn out, and as you've found cleaning will only work a few times before the carbon becomes a hard non-removable coating on the porcelain insulator that permanently shorts the plug. Find out what's up with your motor, get it to run clean and your plug issues will go away. There should be virtually no deposits on your spark plugs in these unleaded fuel days.
Click to expand...
 
olChris said:
Mk3 with original leads, caps/coils and electronic (Boyer) ignition runs perfectly with new plugs for a while..

Could this be caused by my "old" coils, boyer, and dodgey old champion plug caps that look fine but not real sure about how good their contact is with plug tip...
Click to expand...

Maybe you answered your own question...
 
The 2 most common problems that cause this.

Rich mixture. The plugs insulators should stay white with unleaded fuel. If you can run a 6 grade plug on the highway without pinging or holing a piston -then the mixture is too rich.

Weak ignition. New plugs with sharp edges fire with reduced voltage. After a little use, the plugs require more voltage to fire and your ignition system may not be able to provide it.
 
Not Norton, but sparkplug data point nevertheless. 2005 Toyota Sienna, V6, 272,000 mi, original plugs, runs like an electric motor, valve covers never removed. Each plug has its own coil connected directly to the plug - no plug wires in the conventional sense. Replacement plug codes (Denso SK20R11, NGK IFR6A11) are both for iridium plugs.
 
WZ507 said:
Not Norton, but sparkplug data point nevertheless. 2005 Toyota Sienna, V6, 272,000 mi, original plugs, runs like an electric motor, valve covers never removed. Each plug has its own coil connected directly to the plug - no plug wires in the conventional sense. Replacement plug codes (Denso SK20R11, NGK IFR6A11) are both for iridium plugs.
Click to expand...

I pulled the plugs out of my 2004 Colorado with Iridium and individual coils at 140K Miles...the gap was about .150" You might want to check those in your Sienna :D
 
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