Fouling Spark Plugs

Hi. I have the 82 XJ750J Maxim. I have owned her about 9 months now. It set outside for 3 years before I bought it. Early in the spring, I had the plugs changed, new tires and the carbs cleaned out. I have been running the 93 octane gas in it. In early July, it started missing out with about 1/2 tank of fuel. I thought that it was bad gas, or (since not too many people are springing for premium,) there might be water in the gas. So I added some Seafoam and changed the plugs. The old plugs were very dirty. 1 or 2 might have been oily. I have been getting a small oil spatter on my left boot when I ride, so I thought that the gasket is leaking somewhere.

Now, six weeks later, it started missing out again last week. I tried to start it on Thursday, and just ran the battery down. After charging up the battery, it ran as rough as ever.

Does anyone have any idea WHAT would cause the plugs to foul? Where should I look to try to fix this?

Thanks

 

is it an oily fouling, or carbon fouling?

carbon fouling could be something as simple as you fuel mixture being too rich, or your air filter being filthy, and not letting enough air through.

 

Carbon fouling. Not oily. The carbs were just cleaned in April. Could the floats stick already? I have been thinking about increasing my use of Seafoam

 

Have you adjusted your fuel/air mixture? If its too rich it could be causing it

How do you use your choke? If you leave your choke on when you begin to ride then your mixture will be too rich- causing carbon fouling

is your air filter clean and free of oil? If its in bad shape it could be restricting air flow enought to leave your mixture running rich- causing carbon fouling


Those are atleast some places to start.

 

If you have NGK plugs in it - pull them off and throw them in the ravine across the street (OK if you do not have a ravine across the street, UPS them to me and I will throw them in the ravine across the street from my house for you) and you swap it out with Champions or Autolites or AC delco's.
My virago eats NGK's - 1 month per set, the GS reacts badly to them, some GS'es react more than others, the maxim X also didn't like them, and I got champion 809 in the X, and my vulcan also didn't like NGK's. Champion 810's in it. I have NGK's in my air max (sitting awaiting tank reseal and pipes re fit) and my KZ440, but they are old plugs and I am pretty certain the last 3 years or so have been the turning point for NGK's.
Try it. Then complain I mislead you. No kidding - NGK's have turned to sheite in the recent past.
Cool.
Srinath.

 

1. No I have not touched the fuel / air mixture. I use the choke when I start it in the morning. Then about 2/10 of a mile down the road, I shut it off. (Only choke it about 1/2 way) I put in the air filter in June. I will check it out. It is the simeple Fram filter.

And yes, the new and the old plugs are both NGK. I am not sure what model # to use for other brands.

 

Perhaps removing the air filter has some effect.. try it. IF.. problem clears then you've found the cause

 

Srinath, I've run Autolites in the past and the Max was MUCH happier with the NGKs. My experience has run counter to yours it would seem. I'm not a Champion fan in any way (to many broken plugs on countless engines). My beasts have all performed better with the correct NGK installed. How many times have you noticed this issue with your machine? I'm really puzzled given your experience and mine. Hope we can ferret out this problem, you've got me worried now (about the plugs, not you.

 

I'm with Robert on this. Nothing but NGK in all my petrol engines. I've had many problems with champion and other brands and would be interested on more info on the specifics of how your virago "eats" them.

Sometimes the difference between plugs is a slightly different heat range and changing brands is usually covering an inherent problem. Are they fouling, corroding or cracking the insulators.

I've found wear on electrodes minimal on NGK's but every set of champions I have removed have all had rounded electrodes.

 

The plugs are fouling. I changed them last week with Autolite 63, because NAPA did not have NGK in stock. I also added 4 oz of Seafoam and got terrible mileage this weekend, but it ran like a top. I have a friend who used to sell Yamaha's in the 80's. He looked at my plugs and thought I should buy hotter plugs. He said that the NGK NG7ES (not sure if that was the number) that I was using, I should buy an NG8ES. The higher the number, the hotter the plug. If I buy Autolite's buyu a lower number (like 53 instead of 63).

 

Sounds like a plan. I've run the 8ES in my beast without any problems (it was a one-time thing, only plugs they had at the time).

 

Hotter plugs - the BP6ES is hotter than the BP7ES. The funny thing is, they both convert to the 63 autolite. My guess is that either BP6 or 7 is the same or the 63 is the hotter version only.
The BP6's worked great in my 535 but the 1100 seemed to prefer the 63's over both the BP6 or 7. Yea it worked but the 63's worked much better. Champions also worked great, in fact better than the 63's even.
I hear you on the broken plug thing. I broke a champion just putting the wrench on it. That lead me to the 63's. Champion porcelain is just a whole lot more fragile I think.
On the GS'es once in a while I'll run into a bike that just did not like the NGK's. One bike I sold last year, the bike I swapped with someone a week ago and one more I worked on 3 years ago were really particular about not having NGK's. I haven't tried autolites or AC delco's on them. Champion was me first stop. Worked great. I have swapped in older NGK's and have had good luck, new is lousy. Maybe they had quality issues, or fuel composition has changed and they dont work too well or heck, I heard they are made in a factory in mooresville NC, and I live 20 miles from there, so our stock of NGK's are from that factory, and that place has issues ... maybe.
Cool.
Srinath.

 

I'm partial to the Autolites myself, they have (according to the folks at Jacobs Ignition) the hardest electrode in the industry. I ran the 64's in my VW Rabbits and Scirroccos with wonderful results for years (not on the 16 valves, they don't like them). NGK is a bit easier to consume, I'll ceed that right now, but my motors are happy campers with them. Having found the happy place, I've not bothered to experiment with anything else. One more note, I've run SplitFires in my Sentra, VW, and my GTO and they were about the most worthless pieces of junk I had ever run. Big marketing gimick those things. Electrical spark will occur at the path of least resistance. Which means, unless you have the perfect eye and can see distance down to the nth degree, your not going to get more than one spark in more than one location, it is impossible (I shouldn't say that because somebody will argue, I just don't know anyone who can set a plug PERFECTLY parallel between the electrode and the terminal). Hope everyone gets something out of all this.

 

I have been getting good results with NGK's and Champions in my 73 Baja. It hates Autolites. My bike still has NGK's in it and they are holding up well to my abuses.

I do index my plugs in the Baja. I think this may be the cause of some peoples bad plug experiences. I sure helps the Baja.

I think the Baja hates the autolites because the center electrode doesn't stick out from the threaded section as far, possibly blocking the spark a little. Indexing helps but I can really tell the difference with the NGK's

 

I went to NGK's web site and found he did tell me wrong. The lower the number the hotter the plug. So BP6ES is hotter than BP7ES. I did check the air filter and it was clean and in place.

What is "Indexing your spark plugs" ?

 

In order to get the opening of the spark plug lined up where the electrode does not shroud the incoming charge, folks will index the plugs using spacers (extra plug gaskets of varying thickness) to get the electrode turned away from the intake valve, thus exposing the incoming charge to the uninibited spark-o-matic. Sound simple? With the head on, simply mark the side of the sparkplug where the electrode is with a magic marker, thread it into the hole and determine its relative position to the intake valve. Use shims of greater or lesser thickness to adjust seat position. There you go, performance tips with a personal touch.

 

Indexing is an old errr... discredited.. notion. True, like it not
I does not produce any measurable HP gains even on race engines (well not entirely true.. experiments have shown a fractional hp increase, thats a fraction of 1 hp.. onna 400 hp competition engine) How does one know the turbulence patterns in a combustion chamber.. at varying throttle openings, at varying rpms, at varying loads? Simply cannot be done with any reasonable repeatable methods... most certainly to those without million $ R&D budgets.
Quite possibly pointing yer electrodes in an other direction might help them fire under less than ideal conditions. BUT this indicates a plug missmatch problem more than anything else. Check out the Plug catalogues.. Online.. there are Thousands of possibilities Choosing the exact right one is serious business.
Sorry fer being a pain here but It's one of those old wive's tales that simply ain't true.. no matter how many times it gets repeated.

 

Hear you on minimal HP gain. Never tried it myself but am familiar with the practice. Knew a pit crew chief that swore by it. Heck, there are even teams on the circuit that still practice this. Every little bit helps is the mantra, even in infinitesimal quantity.

 

Boys and Girls ...

The engine is turning thousands of times per minute.
The power stroke happens so fast it's a small fraction of an eye blink.

Fuel enters the cylinder, the valve closes, the fuel / air mixture is compressed within the cylinder, a spark is introduced to ignite the mixture!

It does not matter how or where the spark is introduced. The spark has little to do with it.

Only the mixture and advance have anything to do with power.
If you need more power ... you run a hotter Main Jet.

If you want to spent the money ... you can get an ignition module that will allow you program a few more degrees of advance. Read the small print.
"Programming the advance ahead of that which is already determined to be the optimal setting for your machine may cause damage to critical components."

Pretty vague. It means advancing the spark for an increase in power might: Blow-out rings, blow-out the head gasket or blow-up the engine.

Just put the plugs in at the right gap. If indexing had anything at all to do with performance ... the manufacturers would be selling kits!

 

True Rick, but the reality is that, even as a miniscule gain, it is a gain. I wouldn't waste the time on it myself but when the big boys are playing for money, they milk the power gains where ever and however they can find them, no matter how small it might be. Look at cowl induction, not too big a gain but free power. Or removing all the accessory belts, only a few hp there but it all adds up. These guys trim weight off, pounds of it, and will shave ounces where they can. It all adds up. Ok, broken record here, I'll stop. But you undoubtedly are aware of the indexing kits/rings available in all the hot rod catalogs (Jegs and Summit, just to name a few that pop into mind. As I recall, Accel sells them too). I think that it does, in fact, show that there is some truth to it all (why would they waste the time creating the product if it wasn't viable?). Of course you could also point out the "fuel econimizer" magnets that the market has still floating around as an example of hoakum that is still being pitched to the smucks that will buy it. All I'm saying is that, for the layman, indexing is a waste of time, but it technically can be said to be benificial. Sound plausible?

 

Sure ... plausible. But, I want to see the results -- both ways, on the Dyno, before I my opinion changes. We'll agree to disagree.

 

There is a lot of information that shows indexing can help gain power as the following quotes suggest, but the original post was about plug fouling and I think indexing can help in that regard.

My old and tired 70 Baja likes the plugs to be indexed to the exhaust valve or they show signs of fouling (carbon buildup in the electrode area) at tune up time. I don't have a dyno to tell if I am getting more power by doing this but my 25 years of experience with this car tells me that the plugs won't show signs of fouling if I spend the extra time. I don't have that much experince with the bike yet, but I will experiment with indexing to see if it makes any difference in plug life.

On the flip side, Indexing doesn't make any difference in my 93 S10 (4.3 V6) Since the engines are radically different, there are probably a lot of variables working here that keep the truck's plugs clean. (Heat range of the plugs, fuel injection vs carbs, water cooled vs air cooled, driving style, etc...) There does seem to be a consensus that Indexing won't hurt the engine's performance so I do it.

"Real-world power gains vary. Some engines or combinations respond differently than others. In fact, all engines will pick up power, but some gains will be more dramatic than others."

http://www.advanceautoparts.com/english ... 001sp.html

"According to Dr. Christopher Jacobs (of Omni-Pak and Pro-Street ignitions from Jacobs Electronics), indexing sparkplugs 'never hurts and sometimes helps'. "

http://www.dodgeram.org/tech/gas/spark_ ... dexing.htm


From NGK's web site
"4. Indexing

This is for racers only !!
Indexing refers to a process whereby auxiliary washers of varying thickness are placed under the spark plug's shoulder so that when the spark plug is tightened, the gap will point in the desired direction.

However, without running an engine on a dyno, it is impossible to gauge which type of indexing works best in your engine. While most engines like the spark plug's gap open to the intake valve, there are still other combinations that make more power with the gap pointed toward the exhaust valve.

In any case, engines with indexed spark plugs will typically make only a few more horsepower, typically less than 1% of total engine output. For a 500hp engine, you'd be lucky to get 5hp. While there are exceptions, the bottom line is that without a dyno, gauging success will be difficult."


http://www.ngksparkplugs.com/techinfo/s ... S#indexing

 

Dr. Jacobs book was a worthwhile investment and the tech support has been top notch. Learned a great deal from his book that gave me a considerably larger understanding about optimizing an ignition system.

 

I having the same problem with my 82 XJ750 Maxim. I tried 6ES and it fouled them as well. I added seafoam in mine today and went for a ride. I have been told, mine is running a little rich, so how do I adjust for this. By the way what plug did you finally try. I'm willing to try the Champion.

 

I could not get the Champion at my local NAPA without a 2 day wait. I got the Autolite 63. I took them out last week and they look fine. Also added 4 oz of Seafoam to the last tank of gas too.

 

My '81 Seca seems to be partial to the NGK BPR7ES. Whenever I used the standard issue NGK BP7ES she idles high (3-4k rpm) and I look like a douche at stoplights 8) . Does the R mean an extra resistor? Why would simply swaping these plugs affect the idle?

 

R does indeed refer to an added resistance. The additional resistance makes for a hotter plug but does retard timing just a hair (takes a little longer for the secondary voltage to ionize the air gap and make the jump). That might be your lowered idle speed but I'm guessing now. Does anyone want to hazard a guess?