Spark plugs fouling

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wheels
Posts: 50
Joined: Thu Aug 26, 2004 4:47 pm
Location: southern illinois

Spark plugs fouling

#1

Post by wheels » Wed Sep 15, 2004 8:37 pm

i know there ws a thread about plugs a while back, but i was wondering about plugs and gap. since i've had my current pan (65) it has fouled three sets of plugs in alittle over four months. for two months i've just been able to start it and let it run in the garage do to an injured shoulder. harley plugs lasted the longest it seems. then went to napa and got some champions. they look like identical plugs even have the same number down on the metal part but didn't seem to last very long. they were gapped at .025. this may be dumb question but can increasing the gap hurt anything. someone suggested going to .030 or even a little more. the carb seems to be set just right. thanks for any insight.



kell
Posts: 369
Joined: Sat Jun 19, 2004 2:58 am

Re: Spark plugs fouling

#2

Post by kell » Thu Sep 16, 2004 3:08 am

You can try making the gap bigger, but I would ask, if you have plugs fouling how would a bigger gap prevent that? The fouling (gas or oil) will still get on them I would think. And with the bigger gap, fouling will just the bike that much harder to start because both things (wide gap, and fouling) eat up voltage.
So is it dry soot or wet? If it's dry I would suggest, just from my own experience, to try leaning out the idle mixture a little bit.
Another fix is to go one step up in the heat range with your plugs. Slight differences in the heat of the plugs you tried might explain the variation in resistance to fouling that you experienced.
What kind of a carb do you have?

wheels
Posts: 50
Joined: Thu Aug 26, 2004 4:47 pm
Location: southern illinois

Re: Spark plugs fouling

#3

Post by wheels » Thu Sep 16, 2004 5:21 am

i have a linkert carb. the soot is dry. i leened it just a tad and took it out and gave it a good ride. the front plug is alittle black and the back looks good. it ran really good even though it hasn't been rode for a good five weeks. thanks for the reply. this is the second time you have helped me.

Red Haired Boy

Re: Spark plugs fouling

#4

Post by Red Haired Boy » Thu Sep 16, 2004 2:31 pm

Wheels, Just had the same problem with my pan, front plug would foul w/black soot, I had to lean the carb(Linkert) a few clicks more than the manual calls for, also as mentioned a hotter plug might help..Seems that in my case I need to adjust the carb by the looks of the front plug instead of the book..Good luck..

wheels
Posts: 50
Joined: Thu Aug 26, 2004 4:47 pm
Location: southern illinois

Re: Spark plugs fouling

#5

Post by wheels » Thu Sep 16, 2004 4:17 pm

thanks, i know this might open a new can of worms but do you guys out there think one plug is superior over another. i know the guy that does my major work hates the champions. they appear to be the same plug as the h-d and half the price. is .030 gap ok. thanks

Cotten
Posts: 6791
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois

Re: Spark plugs fouling

#6

Post by Cotten » Thu Sep 16, 2004 11:42 pm

I have nothing against any brand of plug, unless it is yellow.

But I think you guys are overlooking the obvious if one cylinder is burning significantly different than the other.

Don't blame the plug!

Snake33
Posts: 31
Joined: Wed May 26, 2004 6:23 pm

Re: Spark plugs fouling

#7

Post by Snake33 » Fri Sep 17, 2004 1:10 am

Uh....eml?

Cotten
Posts: 6791
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois

Re: Spark plugs fouling

#8

Post by Cotten » Fri Sep 17, 2004 2:46 am

EML, or a worn points cam, or leakage around the plug, a resistive plugwire,or any number of things.
A significant difference between cylinders is still a sign that something is amiss. (I don't sweat a little difference, if neither fouls nor burns dangerously lean.)

I tail-chased on a perfectly tuned motor once, until I realized one head had been repaired with an insert. It insulated the plug, making it appear leaner.

Still, the plug is not at fault.

Whoops, I just remembered another caveat:
NGK plugs are now resistive.
If you can measure any resistance on a plug at all with a common ohmeter, don't use it with a points ignition.

wheels
Posts: 50
Joined: Thu Aug 26, 2004 4:47 pm
Location: southern illinois

Re: Spark plugs fouling

#9

Post by wheels » Fri Sep 17, 2004 5:26 am

i haven't had this bike too long, around four months, and havn't been able to ride for two months due to shoulder surgery. i have rode it a couple of times the last few days. there isn't too much difference between the plugs but there is a difference. also i noticed after yesterdays ride a little oil leaking on the front cylinder. looks like it is comeing from between the head and cylinder. i didn't know a lot about the bike when i bought it. got it off the internet but thats another story. igot luckey on this one because it runs good . i hope to make till winter when i can take care of a few problems like the leak amd a tranny leak.

kell
Posts: 369
Joined: Sat Jun 19, 2004 2:58 am

Re: Spark plugs fouling

#10

Post by kell » Fri Sep 17, 2004 7:25 pm

Cotten, you mentioned resistor plugs being inferior for use with points. I know non-resistor plugs work better. But go tell some guy (even guys with years of experience with bikes and other motors) that you want a non-resistor plug and get ready for the scornful lecture. It has happened to me more than once, at bike shops, Harley-oriented and otherwise.
The problem is finding non-resistor plugs. Like on my double-plug STD heads I need a long-reach plug, on the right side they need 5/8" hex to fit. Non-resistor? No such thing. On the left I can use the Champion N11YC, which has a 13/16" hex. The biggest advantage of non-resistor plugs, versus resistor plugs, is the superior ability of a non-resistor plug to fire when fouled. This applies whether you have points or electronic ignition. But if the plugs aren't fouled, I'm still undecied about the difference in performance between the two kinds of plugs.
They first came out with resistor plugs in the sixties so you wouldn't hear a buzz on your car radio. Now everybody seems to think if you put non-resistor plugs in your car it would kill the computer or something. Not! There are even some capacitive discharge ignitions now that require non-resistor plugs, and these aren't going around killing computers.

I understand there is a federal law against using non-resistance plug cables on public roads. Wise legislors must protect us all from

ELECTROMAGNETIC INTERFERENCE


Officer! That man is interfering with my car's computer!
Don't worry ma'am, we know how to deal with people like him. BLAM! BLAM!

Cotten
Posts: 6791
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois

Re: Spark plugs fouling

#11

Post by Cotten » Fri Sep 17, 2004 11:02 pm

It is my contention that resistor plugs will foul when non-resistors will not,..on our 'primitive' ignition systems.

My knuck runs great for extended periods on old NGK A-6s (or any other appropriate plug.). The new A-6s pull me off the road after about 30 miles, showing no visible fouling.

After a few go-rounds with an arrogant NGK representative, I sent three cases of them back for "testing", at his request. That was months ago, and I'm still out a considerable investment, not to mention my embarrassment with customers that returned them with similar results.

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