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Engine eating up spark plugs for breakfast, lunch and dinner

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Engine eating up spark plugs for breakfast, lunch and dinner

Posted by aled_corps at September 18. 2017

I'm still having issues with spark plugs failing since the engine rebuild which I can't seem to resolve. I got about 500 yards from the first one, 35 miles from the second, 15 miles from the third, one start from the 4th without moving, and the latest one has failed before the bike even fired up. Apart from The first 'Champion' plug, the rest have been 'NGK'.

I clearly have an issue that's more than just dodgy plugs which I need to sort. These plugs still have spark when out of the engine, but must not have enough of a spark under compression.

Maybe its the boyer electronic ignition which clearly works, but could it be wearing out plugs somehow. Or could the coil be playing up?

Could it be something to do with the battery?

Could it be the setup of the Amal Mark 1 concentric 28mm carb? It runs ant ticks over really nicely when running, so it seems to be set up really well.

Are there 'heavier duty' spark plugs available at all which create a bigger stronger spark?

Thanks
Aled

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by jonathan_newton at September 18. 2017

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

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by robert_tuck at September 18. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by ian_soady at September 18. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by christopher_winsby at September 18. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by robert_tuck at September 18. 2017

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

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by Dan Field at September 18. 2017

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

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by Bob Matthews at September 18. 2017

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

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Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by boo_cock at September 18. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by John Shorter at September 18. 2017

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

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by john_evans1 at September 18. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by Barry Carson at September 18. 2017

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

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by aled_corps at September 18. 2017

Thanks all, I wanted to reply to the comments:

I've been in contact with Al Osborne (even though he's on holiday, he had time to call my father in law to discuss).  He doesn't think it's the boyer ignition at fault here, but we can send it back to boyer to test if needed.

I didn't have this issue before Mike Pemberton's engine rebuild, so the only difference there is that the engine is now in much better condition with better compression. Id expect the plug to withstand that compression.

Al Osbourne did suggest a softer plug that will run hotter, but i'm using NGK B6ES which I believe is the hotter version with B7ES and B8ES running colder.

I've checked the battery connections, and they seem fine.

I timed up the engine with a strobe.

The wiring is the right way round on the boyer

I don't have access to another bike with the same engine that I could try these plugs in I'm afraid.

The plugs look ok when pulled out, not wet at all, maybe a bit sooty, but not white, to be honest they look as expected.

I'll replace the HT lead this week, as well as changing the suppressed cap.

I will also try a different slide and/or needle position in the carb to see if that makes a difference, though when it does start and run it sounds great, which makes me doubt the carb setup is wrong.

the plugs have come from feked.com which I've always found to be a genuine supplier of parts, so I don't think they are dodgy plugs.

I've got a couple of things to try t least, so I'll report back after I've done all that

 

thanks

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by Dan Field at September 19. 2017

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

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by Neil Wyatt at September 19. 2017

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.)

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by christopher_winsby at September 19. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by Gordon Johnston at September 19. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by Neil Wyatt at September 19. 2017

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?

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by john_evans1 at September 20. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by Barry Carson at September 20. 2017

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

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by David Cooper at September 20. 2017

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 perhaps not 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 a replacement 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 cap breather hole is clear?  If partly or fully blocked, that'll stop it at an unpredictable distance, and also can easily rectify itself after a couple of minutes spent swapping plugs.

 

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by aled_corps at September 21. 2017

Hi all,

 

I've left it a while before attempting to start it again, and also taken a plug out, checked it, put it back in, and it woudn't start, but when I change it to a new one, it starts right away which is my main reason for blaming the plug. I'll check the fuel tank breather, but as I can easily flood the carb and it still wouldn't start, I can't really put the blame on fuel.

 

Having said that it may be a combination of things. Failed plugs, but at other times it could be another issue and I've been quick to blame the plug again.
Yesterday the bike started 6 times during the day with no issues with a plug that I thought had failed the day before.

I have a 'suppressed' plug cap, which apparently reduces the spark a bit (Is that right?). I've tried a non suppressed cap, but yesterday it started with both, so not sure if that makes any difference.

I also changed the slide in the carb to one with a bigger cut out, '3.5' rather than '3'. It still starts and runs nicely with that, and the plug is not so sooty. So I've left that in to see how it goes.

Last night I took it for a test ride, 30 miles with a stop in the middle and the engine sounds fantastic when going and pulls nicely. I did struggle to start the engine on my way back though, it back fired twice before finally starting on about the 12th kick. It then ran well all the way home. I would add that it was a fairly cold evening.

I'm not yet at the point where I'm confident it'll start each time, but I'm getting there slowly. I'll continue to try some of the suggestions you've all given me.
RGM have a higher grade spark plug 'NGK6EV' which are £9 each compared to the £2 'NGK6ES'.  I might try those with the  assumption that the extra cost must account for some sort of better quality!
Thanks to all for their contributions so far.

 

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by Neil Wyatt at September 21. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by christopher_winsby at September 21. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by George Phillips at September 21. 2017
I think you'll find, Aled, that the cutaway only comes into play from1/8 to 1/4 throttle opening. When starting, the throttle (at least on my '55 ES2) is kept closed. So the poor starting may be nothing to do with cutaway? George

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by ian_hind at September 21. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by john_evans1 at September 21. 2017

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.

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by Barry Carson at September 21. 2017

is the exhaust decompression mechanism ok

are the tappets to tight.

 

Barry

Re: Engine eating up spark plugs for breakfast, lunch and dinner

Posted by George Phillips at September 22. 2017
Just to back up what Neil says, my '55 ES2 has a no.4 cutaway as per the book. Works fine. George
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