Spark plugs

For many years now I’ve been a fan of small electrode iridium plugs, generally using NGKs. This is because I learnt from experience that ‘normal’ plugs would fail too easily in a race / track bike. I started running them in race bikes, liked them and stuck with them.

Recently I added a restored T140 to the shed inhabitants. Being freshly rebuilt, it’s possible it burns a tad more oil due to fresh honing. The carb setting were also off being too lean, resulting in a very slow warm up which meant over use of the choke (an enrichenimg circuit on mk2 Amal’s) subsequently making it too rich.

During the time spent sorting the carbs, on 4 occasions I was side swiped by duff plugs. The first time it happened I assumed a faulty plug. By the third time, even I was thinking there might be a link here. I changed to fancy Bosch plugs, and one failed. I’m talking 4 plugs failures inside 50 miles... each time being certain that the plugs MUST be fine because they’re NEW... very irksome !

So, long story short, I reverted to standard issue Champion plugs, of the type I’ve not used for years. I’ve done nearly 200 miles on these so far (when the weather allows) and they’re running perfectly.

Then by coincidence, I read in this months Classic Bike Guide (see pic below) about how modern plugs are designed for clean modern engines and how these ‘Brisk’ plugs are designed for ‘classic’ engines. I’ve not tried any yet, but probably will do so.

SO:
Is this a common finding amongst you fine fellows?
Do ‘exotic’ plugs foul more easily?
Have I simply learnt what you knew all along?
Has anyone tried ‘Brisk’ plugs?
Should we emit spark plugs altogether and run diesel?


Here’s the piece about Brisk plugs:

Here’s the link to F2 Motorcylces Brisk plug page:

http://www.f2motorcycles.ltd.uk/Brisk Spark Plugs.html

Over 2 years ago I bought a pair of expensive Iridium plugs for my commando' I put them in for the south island rally down to Dunedin in which I covered 3145 miles. On the way back up the lower North Island, the bloody things became lazy, causing backfiring at light throttle on th overrun. This in the past has caused broken throttle slides so I changed them out for a pair of N7Y plugs. When I got home I sandblasted them and put them aside. I put them back in fro that trip last week to Akaroa and they went well,, but the bike became harder to start, the further I went. I persevered and made it back to Mangawhai where I took them out and scraped a carbon build up from them. After putting them back in , the bike started first kick again. Next day i rode home. unloaded all my gear then had a rest. 2 hours later i decided to change the engine oil etc but because it had been sitting, attempted to start it again to make sure most of the oil was in the tank. it would not start, so i shoved 2 new BP6EY plugs in, and it started first kick.
In Conclusion, I would never by Iridium plugs for this bike again. I will stick to the BP6EY or N9Y plugs for the local running I do and put in N7Y plugs for the long trips.
Dereck

We tried some Brisk - part number DOR14LGS a couple of years ago.

These were recommended by Brisk themselves as a direct equivalent to the Champion N7Y



They sooted up very, very quickly - having to take them out and clean them every time we wanted to start the bike from cold.

I have a theory about the common NGK and Champions being counterfeit.
Even the Green Sparkplug Company (the goto place in the UK for classic bike plugs) confirmed they had received batches of counterfeit plugs in the past.

For this reason I switched to Bosch, which were no trouble at all.

Someone recommended I try Denso IW22 so I did.
Superb plug, they run so clean, and don’t foul like others I have tried.

I have been using NGK Iridiums for 10+ years and never had a failure.

IMO, there is not much gain in exotic spark plugs, I used the N7Y for the last 40 odd years in the Commando and never had problems.

I use Denso Iridium IW27 as a race plug and am happy with them, with IW22s in a 750 V twin road bike.

But I am equally convinced that Iridium is not needed in a road bike with standard plugs working well.

Unfortunately, NGK suffers from their popularity, meaning they are the most lucrative to counterfeit!

Brisk is OEM on Czech bikes, so no surprise really that plugs work well in what they are designed for, I learn't whilst riding in the US that Harley plugs work best in Harley bikes!

Worth a try! But I have gained the impression on here that Champion have upped their game over the crap they sold for a few years.

kommando said:

I have been using NGK Iridiums for 10+ years and never had a failure.

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Do you use them with standard Amal concentrics fitted?

kommando said:

I have been using NGK Iridiums for 10+ years and never had a failure.

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Likewise. I just got 15,000 miles out of a set of NGK Iridiums. I suspect that most Commando owners run their bikes on the rich side, causing problems with fouling. I only changed the plugs for peace of mind, The old ones were still working fine.

I still like the old Champ N4G plugs. Easy starting and rarely fouling. Someone smarter than I postulated their anti-fouling aspect is due to the heat range (4) which would be much too hot in a conventional plug, but the gold wire electrode stays clean without any risk of holing a piston or other too-hot problems.

Just looked at another box of 10 on fleabay for $2.75 per plug. What decent plug DOESN'T cost that much? Would a hotter-range NGK Iridium do the same thing?

Edit: just bought a box of 10 for $26.50 shipped.

baz said:

Do you use them with standard Amal concentrics fitted?

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Yes, on 3 different bikes, all with chokes fitted. 2 Boyer digital red boxes and one points.

Love me some Champion Copper Core in my old bikes, less fouling. NGK "projected" plugs are OK but foul a lil' easily. Bought counterfeit ones 3 times online from Peebay so now I only buy from auto parts store.

I think modern fuel quality has some negative affects on our usual plug choice .... for many years I ran either the n7y or bp7e with good performance ... than gradually noticed some degrading ( hard starting , black plugs ) .... once I started with the race fuel mixed with high test 25%/75% plugs look like they used to 25-30 years ago , can get several years of light use out of a set now .....

Craig said:

I think modern fuel quality has some negative affects on our usual plug choice .... for many years I ran either the n7y or bp7e with good performance ... than gradually noticed some degrading ( hard starting , black plugs ) .... once I started with the race fuel mixed with high test 25%/75% plugs look like they used to 25-30 years ago , can get several years of light use out of a set now .....

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They look like they used to because you put lead in the fuel! It is the lead that gives colouring you can read.

Why go to the cost of race fuel if you don't need it, I race and still don't use it because I use a fairly low compression ration for a race bike.

Yup , lead not only makes plugs look familiar , also provides other enhancements .... I run a high compression Combat , so the addition of the 25% race gas gives performance a little kick .... fouled plugs can be a real drag , sometimes making you scratch your head in wonder of why .... yes 114oct gas is costly but a can lasts me quite a while , since I started using it no more of the issues similar to what discribed above , makes sense for me , maybe not for everyone ..... I too have been recipient of knock off plugs and that just plain maddening ....

Hi octane fuel has a little less energy per unit than low octane.
If you need it to prevent detonation, by all means it's a good choice.
114 Octane doesn't add performance, just the opposite. The added Octane slows the burn to prevent detonation.
You only need enough Octane to stop detonation.
It will help keep the engine together if you are running extremely high compression, like 12 to one .
I've just recently switched back to Champions as all of my eBay NGKs were fakes.
The NGKs purchased at Napa appear to be genuine, however I believe starting is a bit easier with Champions.
Glen

Performance I was referring to was longer lasting, cleaner plugs ,easy one kick starting and possibly longer life engine components due to lead ....

On a side note while searching for a replacement for my G35 , I was looking at Asian sporty cars , wish I could remember the exact details ... basically they said if you ran high test you had like 330hp and on regular gas ‘bout 305hp .... can’t remember brand or exact numbers but similar .... surprised me !

Craig said:

On a side note while searching for a replacement for my G35 , I was looking at Asian sporty cars , wish I could remember the exact details ... basically they said if you ran high test you had like 330hp and on regular gas ‘bout 305hp .... can’t remember brand or exact numbers but similar .... surprised me !

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With modern ignitions that can sense detonation, ignition timing is automatically adjusted for the octane. The performance difference is due to the timing not the octane.

In fact 2017 Dodge Challenger srt makes 808hp on regular fuel and 840 on 100 oct. gas .... pretty cool , eh ! .... found that info pretty easily on line , the old truths just are not applicable any more ....