Plug Fouling

[A10Boy]

Yes, wise words A101960.

Quote
I would not use NGK plugs in any British bike. I have tried them and had nothing but trouble.
I stick to Champion.

Its funny how we all have different experiences, I had NGK plugs in my A10, when I rebuilt the engine I fitted new Champions, one failed after about 50 miles or 3-4 heat cycles, went back to NGK and no more probs.

ps, Her indoors is at work in the morning, the forecast is good so the plan is to do some serious miles up in the Cotswolds... Bring it on..

And what happened, started her up, warming on the drive while I was putting my helmet on and suddenly stops firing on RH cylinder, -- lovely new NGK failed.   

[michaelfish]

My 1960 A10 G.Flash is suffering from exactly the same symptoms.  It was running well, back in 1966 when I put it into retirement. Brought out from its sleep recently,after a bit of fettling it started 3rd kick!  However a short trip down the road and it was mis-firing with the plugs sooting up.  Carb.seems O.K. Timing has never been interfered with.  I have spoken to Gary at SRM and he is convinced that after all these years the condenser is the most likely culprit, so thats my next step.

[Brian]

About 20 years ago I restored a Triumph twin ( first and last one I have owned) and when I got it the maggy looked perfect. The insulation was rock hard on the armature and it threw a very good spark so I put it on the bike. First ride after about 50 miles the armature melted stripping the drive gear and I had to walk home, not impressed ! Its not easy getting a melted armature out of a maggy body either.

Anyway to get to the point, since then every bike I have owned the very first thing I do even if its supposedly a brand new maggy is to get the armature rewound and the body remagnetised if necessary. I am lucky to have a very good magneto specialist to do the armatures. Use only solid copper wire and the best caps money can buy. Do not buy cheap pickups, get them from a reputable supplier, those plastic hexagonal ones you see are utter rubbish.

Since I have been doing this I have never had a failure and all my bikes are one kick starters.

On the subject of plugs, I have used NGK's for nearly forty years now and have always sworn by then but over the last five years or so I have had a few fail. One would not spark at all brand new out of the box. I wonder if they are manufactured under license in Taiwan (my apologies if there are any Taiwanese reading this) or somewhere and the quality has gone downhill in recent years. I used to use Golden Lodge's in my race bikes in the early seventies, anyone remember them?

[groily]

As to the origin of NGKs, I don't know if it's true, but I was told recently that they are made in Japan and in France. The Japanese ones apparently are better. Why am I not surprised?
I have been using them for years too, but have come across a couple of dodgy ones, like Brian, in the recent past. However, the B6HS's (I think) in my A have done best part of 25000km and are good as ever, I've successfully run B7ES and B8ES in other twins for ages, and find BP6's (with the sticky-out nose but never with an R in) good in another beast.
Friends with other marques have had a few probs with NGKs from whichever source, however, and their name is mud thereabouts. But they are easily available over every counter . . .
To be safe I carry Champions in the toolboxes just in case . . . . but to be fair I have had dodgy Champions too over the years.

[rocket man]

and they call lucas the prince of darkness

[Mosin]

Well, to bring things up to date, I have finally got my bike running again. I think the problem was that the original left hand mag picup was U/S and the replacement part which I bought was also faulty. Eventually I got hold of a third pickup, cleaned it meticulously with petrol and a small artist's paintbrush and left it to dry out for a couple of days before fitting a brand new brush and reconnecting the original lead/plug cap. Result: it fired immediately!

I have now covered about 30 miles on it and to my frustration, I am exactly back where I was three pages of posts ago. The l/h cylinder is running fine but the right hand one is sooting up again.

Grrrrrrr.

[RichardL]

By "sooting," I am assuming you mean completely dry and dusty black; no wet oil or odor of gasoline on the plug; still firing on two cylinders the entire 30 miles; left plug is a delicious chocolate brown. If all these are true, then, by the education granted to me at the The A7/A10 Forum University, I must assume that your problem is induction bias, to be cured by a wedged-shaped gasket fitted between drip pan and head and causing the carb to angle toward the left cylinder. If, after this, both sides are equally a bit sooty, then, mixture is too rich.

As an undergrad, I welcome any correction from faculty.

Richard L.

[Mosin]

The head of the r/h plug is sooty and dry. There is a bit of oily wetness on the threads. and it seems to be missfiring intermittantly. This seems to be worse at low revs, but I might just be imagining it. Because the problem is not there all the time, it is quite difficult to diagnose accurately, and I am cautious that I may be desctibing symptoms of a totally different problem which are just making the original issue!

I have a 20 mile run home from work today and when I get there I will take both the plugs out and get some photos so people can see what they think. That might be easiest!


Simon 

[Mosin]

OK, I took advantage of the unseasonably nice weather and had a really good run home from work today (about 30 miles). For the most part, the bike ran absolutely fine with only a few blips. On checking the plugs, I found that while the right one was a bit sootier than the left, it wasn't too bad and the electrodes were both clean. This set me a wonderin'...

The symptoms I have been experiencing were a sudden loss of power, particularly when the engine was running at low revs or ticking over, or if I had just closer the throttle having rounded a corner or something. This loss of power usually lasts somewhere between one and ten seconds before full power is returned. However, I discovered that by pulling in the clutch and giving the engine a quick rev, this would usually return me to full power immediately.

I have always associated these types of symptoms with the bike failing on one cylinder, but the nature of this power failure coupled with the engine's tendancy to return full power at higher revs has made me question whether I might be barking up the wrong tree altogether. Rather than being a total temporary ignition failure on one side, could my problem possibly be something to do with the auto advance unit sticking?

Simon