Engine eating up spark plugs for breakfast, lunch and dinner

What exactly goes wrong with the plugs Aled? erosion or contamination??

If the plugs are sooty black on the insulator that will stop them working especially if the ignition is a bit under par. My 99 was running very sooty till I unscrewed the pilot mixture screw half a turn,plugs now not missing but still a bit dirty so I'm going to drop the needle a notch although the bike exhibits signs of weakness till well warmed up. It appears I have a weakness in the bypass part of the range and richness either side. This is probably wear in the body giving a slightly loose slide.Fuel also seems to be a little inconsistent (as its allowed to be) ,its not made to suit carburettors anymore as current engines are all FI with O2 sensors and continuous automatic adjustments being made.Current plugs don't cope well with rich mixtures as the insulators are no longer glazed in manufacture and contamination gets into the porus insulator and does not get properly burnt off even if the mixture is right at larger throttle positions.

The problem with modern plugs is that the nose of the insulator is unglazed so once it gets contaminated with carbon it's impossible to clean (well maybe by shotblasting like we used to do in the old days....)

I'd suggest that it's running rich enough to coat the insulator nose hence as you say sparking outside the engine but when subjected to compression will just track over the carbon.

I have an antique Lodge plug from the ES2 which I keep on one side just in case.

I can't honestly see how your ignition setup could cause them to fail. On the other hand, maybe the ignition is so weak that even the slightest resistance stops the vital spark from getting through.

Where did you get the plugs from? The Green Spark plug company has a good reputation for reliable plugs that work. My neighbour had trouble with his Trident. All new plugs he said, I got them at an auto jumble at a good price. Only one worked properly out of six I tried, gave a good spark against the head but broke down in the engine under pressure. I got him three from the Green spark plug company and it has been ok ever since. That was back in 2014.

There has been fake NGK plugs on sale in the past.

My ES2 runs rich and burns oil with no problem (mag ignition) my opinion is unless the plugs are fake, and you have tried 4 then the problem is likely to be elsewhere, it might be worth checking the resistance of the coil, it is possible that you are not getting enough spark on compression, I am having that problem (I think) on my twin with a Boyer.

Have you set the timing with a strobe? I'm not sure how you test a Boyer box, but that may be my next question. I'll be dropping Al Osbourne a line, he is always very helpful.

dan

Have you tried the plug cap? Remove it from the HT lead and wire the copper core from the HT lead directly to the top of the plug connector, if no different at least it's another possibility ruled out.

I believe you can send your boyer box directly to them for testing if necessary.

http://www.boyerbransden.com/faultfinding.html

Further Help

If you still can't find a solution from the information above and continue to experience problems please contact us: Fax: 0044 (0)1622 730930 or Email: help@boyerbransden.com

Or you can return any Boyer Bransden parts for testing to: Boyer Bransden Electronics Ltd, Frindsbury House, Cox Street, Detling, Maidstone, Kent, ME14 3HE. The cost of this service is £16.73 including return UK postage. Please enclose your full contact details and a brief description of the problems you are experiencing. You will not be charged for this service if your part is faulty and under warranty.

Silly question, but nobody has yet asked. Do the plugs work in another bike? Can you try some plugs from another bike that is running well?

Fair comments from those who ask what state is the plug in. is it burnt, sooty, worn or what? We need info to diagnose.

If you need to take a spare plug with you, do not take a new one .Always take an old one that has proven good rather than a new unknown job.

If an old plug has proved good, why was it ever replaced?

No experience with Boyer but if it still uses the ignition coils check the wiring is the correct way around. Reversing the connections at the coils can cause burnt plugs.

6 volt thorspark ign fitted, as i found out i had a bad connection inside the battery its self where the terminals met the plates. it caused engine to backfire if you got it running it would perform ok until i suppose the bad connection reared its ugly head then would cut out hard to get going when you tried the lights and checked the charging it all seemed normal until you placed a full load on the battery then the fun started along with vibration it all has an effect. i replaced the battery all ok. not saying thats whats wrong with yours but just relaying what happened to mine.

Barry

Don't forget to check the coil, or swap it. That's my next job. At least mine doesn't eat plugs it just cuts out on WOT. I doubt it's the plug not being able to take the compression, but when the plug is under compression the spark needs to be stronger to jump the gap than when it's just ticking over or starting. Hence the need to make sure it's as strong as it can be. I do know that the plug insulation is also not as durable as it used to be and once a plug is knackered it's knackered, and you shouldntbwire brush them. Anna recommends the 3 electrode versions, that might also be worth trying.

Good luck

I don't know why an N*K plug is being used here? We do know there are a lot of fake ones after all. The plug for an ES2 is a Champion N5. (For Model 50 too)

If your bike is burning oil an N8 will take care of that in the short term. Difficult to get this grade now.

Is E0 petrol being used or the deadly EN228, which burns differently to uncontaminated fuel? EN228 also has a short shelf life.

Needle sticking again...(record player needle, that is.)

Previously Neil Wyatt wrote:

I don't know why an N*K plug is being used here? We do know there are a lot of fake ones after all. The plug for an ES2 is a Champion N5. (For Model 50 too)

If your bike is burning oil an N8 will take care of that in the short term. Difficult to get this grade now.

Is E0 petrol being used or the deadly EN228, which burns differently to uncontaminated fuel? EN228 also has a short shelf life.

Needle sticking again...(record player needle, that is.)

There seem to be more crap Champion plugs in circulation than NGK. I stick to Andover Norton, The Green spark plug company, RGM. When people say they have trouble and they got a load cheep it makes me smile befotre I help them. There is a reson why they are cheap.

You can get devices you put between the spark plug and HT

lead that show if you still have a spark with the plug installed.

When you get a good working plug, it is then best to use it as a spare and get another good working plug. No good carrying new plugs as spares if you have not checked them.

I think the hint here is that the plugs are a bit sooty. Drop the needle a notch and then try it. In my experience, NGK plugs are tolerant of most things and indeed i swear by them. However, a fine coating of soot will cause any plug to track.

Got to honestly say that I have never yet had a crap Champion spark plug. That of course doesn't mean they don't exist.

I did however have a Champion plug cap that failed on my 99 during the Spring. Rode home on one pot and replaced them both with unbranded rubber caps I had been using on other bikes for years without issues.

As said before, in the short term a hotter plug will help rid you of surplus oil and deposits in the combustion and give you a clean start, so to speak. Sounds like carburration to me?

Whilst there may be issues with some plugs I feel the debate relating to brands is a red herring. A good plug is a good plug whatever the make.

My m50 is tolerant of just about anything. I currentl have an old n9ycc fitted and it runs well. I have also tried a bosch and ngk. All car oriented devices but none have given trouble.

I really believe the problem regarding burning out the plugs will have other causes. It is obviously easy to test the plug compared to other things but nowadays vehicles achieve incredible mileages from a set of plugs. 50k is not uncommon.

i have heard of this before mainly on injection turbo ect i know its not Norton related .it explains it better than i could .thinking along the lines of over fueling carb wise would extinguish the spark. anything is worth a try.

http://www.evinrudenation.com/owner-zone/spark-plug-indexing-how-to/

Barry

Aled - what makes you even suspect the plugs? You say they look OK when you take them out. A bike will usually carry on running (albeit perhapsnot ideally well) for a good while with entirely the wrong plugs. Certainly with the wrong settings we've all seen both black and burnt white plugs come out of a working engine.

You might well find it starts up again after fitting areplacement plug - but by the time you've swapped it out, it's had a chance to cool down etc. etc.

Are you sure the fuel tank capbreather hole is clear? If partly or fully blocked, that'll stop it at an unpredictable distance, and also can easilyrectify itself after a couple of minutes spent swapping plugs.

I always thought an ES2 used a No 4 cutaway on the standard sized carb? If using a bigger carb then a 3 1/2 should be OK.

No 4 slide on my ES2 BUT 3 1/2 on my Poor Man's Manx with 30mm Mk 1 Amal.

Previously ian_soady wrote:

The problem with modern plugs is that the nose of the insulator is unglazed so once it gets contaminated with carbon it's impossible to clean (well maybe by shotblasting like we used to do in the old days....)

I'd suggest that it's running rich enough to coat the insulator nose hence as you say sparking outside the engine but when subjected to compression will just track over the carbon.

I have an antique Lodge plug from the ES2 which I keep on one side just in case.

I can't honestly see how your ignition setup could cause them to fail. On the other hand, maybe the ignition is so weak that even the slightest resistance stops the vital spark from getting through.

I had an intermittent Boyer black box. It would cut out, by the tme you check everthing it started again.

Proved by substitution.

Hi Aled, had a very similar issue with a 57`Dominator 99 some years ago, would ride a few miles and slowly start hicupping until it wasnt rideable, then find out the plugs were fouled.

Tried different plugs NGK/Champion, checked the Amal Monobloc setup, checked igntion timing & valve clearences, removed and had the Lucas K2F Magneto professionally checked out, all of these to no avail, they all seemed good. This went on for months trying to think of things to check or change, eventually bit the bullet and bought a brand new Amal Monobloc Carb. Success at last ! it cured the issue immediately has never missed a beat since.

Can only think the Old Amal was worn out internally, although i had changed jets, float etc.. and thought it was OK.

Hope this is of some help to you mate.

Aled

i find it cheaper to buy plugs from motor factors. They generally have a variety of quality brands and all at low prices.

it might be an idea to check the ht lead for resistance using a multi meter and to fit the old type brass terminal to the plug lead thereby doing away with plug caps which invariably will fail.

is the exhaust decompression mechanism ok

are the tappets to tight.

Barry