Plug caps

[dbeardslee]

I got surfing around last night, and found a source for NGK plug caps - at O'Reilly Autoparts of all places. They've got the resistor caps for $3.69 ea., and non-resistor for $1.29. NGK Plug Caps

Looking at the resistor and non-resistor caps got me to thinking. We know plug caps wear out, but I'm wondering if that's just the resistor caps. I run the non-resistor type on Betsy with resistor type plugs, and near as I can tell there isn't anything inside the non-resistor caps to wear out. The metal might corrode in a few decades, but it's basically just a wire encased in a plastic cover.

Any opinions on this?

[BowlingSS]

I was told we need the resistor caps. I do not rem why. I am sure someone will ring in.

Bill

[dbeardslee]

I was told we need the resistor caps. I do not rem why. I am sure someone will ring in.

Bill

The only reason I know to run resistor caps is to keep from causing radio interference with the radio in the cage that's next to you if you run non-resistor plugs like the stock NGK BP6ES. But as far as I know it makes no difference whether you have the resistor in the cap or in the plug itself. But you don't want to double them up with resistors in both the cap and the plug.

[3Phase]

I was told we need the resistor caps. I do not rem why. I am sure someone will ring in.

Bill

What Doug said.

They cut down on RF interference. If you're a "Loud pipes save lives!" person then, "Loud ignitions save lives!" too.

If you use non-resistor plugs like the NGK BP6ES and steel or copper core wires you need resistor caps. You should use 10K caps for the exposed outer plugs and 5K for the inner plugs that are partially shielded by the tank but don't freak out about it.

If you use resistor plugs like the NGK BPR6ES or the NGK Iridium BPR5EIX and BPR6EIX then you don't need and shouldn't use resistor caps.

Graphite resistor type or inductive spiral core wires aren't necessary for either type of plugs and caps and in my opinion aren't necessary.

.

[dbeardslee]

So Scott, what about the caps? Is it just the resistor caps that wear out, or do the non-resistor caps suffer from the same limited life expectancy?

[crazy steve]

One thing to remember... If your ignition produces radio-frequency noise, you can get ticketed for it.

[3Phase]

Steve,

If it makes enough RF noise the cops can't run your plate and you can make good your escape!

Doug,

That is a good question. I honestly don't know how non-resistor caps wear, I've never bought any of them and I've never taken one apart.

I made my own out of resistor caps with a steel slug from a cut off SS machine screw in place of the resistor. They don't seem to be experiencing any wear but thanks for reminding me it's time to clean them in case there's any rust or Galvanism.

.

[dbeardslee]

Doug,

That is a good question. I honestly don't know how non-resistor caps wear, I've never bought any of them and I've never taken one apart.

I made my own out of resistor caps with a steel slug from a cut off SS machine screw in place of the resistor. They don't seem to be experiencing any wear but thanks for reminding me it's time to clean them in case there's any rust or Galvanism.

.

I'm tempted to go buy a new set at O'Reilly's whether it needs them or not. I paid three dollars and change each for the ones that are on the bike at a local motorcycle shop - which kind of pizzes me off when I see them at O'R's for $1.29 apiece.

[3Phase]

I'm tempted to go buy a new set at O'Reilly's whether it needs them or not. I paid three dollars and change each for the ones that are on the bike at a local motorcycle shop - which kind of pizzes me off when I see them at O'R's for $1.29 apiece.

Three or four dollars each was about what they wanted here in Simi and they had some fantasy about me paying another couple of bucks for shipping too because they weren't a normally stocked item. I didn't quite tell 'em to pound sand.

I have to go to O'Reilly's to get some more carburetor and brake cleaner, a can of WD-40, and some Plastigauge so I'll see if they have the caps on sale too. Thanks for the heads up!

.

[dbeardslee]

Three or four dollars each was about what they wanted here in Simi and they had some fantasy about me paying another couple of bucks for shipping too because they weren't a normally stocked item. I didn't quite tell 'em to pound sand.

I have to go to O'Reilly's to get some more carburetor and brake cleaner, a can of WD-40, and some Plastigauge so I'll see if they have the caps on sale too. Thanks for the heads up!

.

No schveat. It's one of those things O'Reilly doesn't normally stock in the stores, but they can get 'em for you in a couple days. They want $3.69 ea. for the resistor type, but the non-resistors are uber cheap.

[TopCatGr58]

Hey Scott, Steve, even Capt. Zap,

Have any of you actually ran your bike and then your car next to it to see if you can perceive any RF in your radio?? I understand that the RF could possibly cause problems with sensitive automotive ignition electronics...but I wonder HOW CLOSE the bike would have to be for it to interfere??

Also...with the lower rpm's of our bikes....7500 rpm, 2 spark pulses per rpm due to wasted spark...so ~15,000 per MINUTE...that's only 250 hz! From what I remember low AUDIO frequencies are more omni-directional whereas hi frequencies are much more directional. Also remember that they travel farther easier that higher audio frequencies. I would think that RF is also Omni-directional....but don't know much about their transmission ability? I understand that AM frequencies are more susceptible to RF than FM. Who listens to AM anymore anyways....and for that matter FM is on it's way out also with the advent of SATELLITE RADIO, as well as iPads/phones/mp3 players.

SO...I'm not worried about the RF from my Non-resistor caps AND non-resistor plugs. This weekend, I'll see about firing up my bike next to my car and see if I can get any interference with any of the electronics.. it has Fm/Satellite/mp3 aux in capability.

T.C.

[3Phase]

They're on sale here too. I had to order them but they found 4 caps in a store up north.

They're the 90 degree caps for the outer two cylinders. I don't think NGK makes a non-resistor 120 degree cap for the inner cylinders but it looks like the 90s have brand new little rubber feet and collars to seal around the wires and the spark plugs.

.

[dbeardslee]

They're on sale here too. I had to order them but they found 4 caps in a store up north.

They're the 90 degree caps for the outer two cylinders. I don't think NGK makes a non-resistor 120 degree cap for the inner cylinders but it looks like the 90s have brand new little rubber feet and collars to seal around the wires and the spark plugs.

.

I've got the little 90 degree non-resistor caps right across the board. I just put a couple zip ties on the wires to hold them up off the motor and away from each other.

Who listens to AM anymore anyways...

Rush Limbaugh?

So TC, what say you on the cap wear issue. Do the non-resistor caps wear out or is it just the resistor caps that have that problem?

[TopCatGr58]

I'll have to see if the ones I have will come apart? I suspect there's just a SPRING in it. I also am using the 90 degree little ones across all cylinders, have the 8mm solid core silicon wires, so wasn't too worried about them rubbing/wearing thru while laying on the head/valve cover. I might wrap them with some zip ties next time I'm under there....will have to pull the tank eventually since last year I overfilled the tank before loading it on the trailer, and so the fuel leaked out...UNDER the custom paint on one side....big area of bubbled paint! Just too much personal stuff getting in the way right now to be bothered with it.

T.C.

[dbeardslee]

That sucks about the paint. I've got a paint job ahead of me too. The tank I painted developed a leak, and I haven't gotten around to painting the current one yet.

Here's another thought I've had periodically on plug caps. Whenever I change wires I always get a cheap set of 7mm solid core automotive wires. The one's I've been using are called Pro Series 2403W's, although I'm sure there are a lot of similar universal type wire sets. These always have automotive type plug boots on the wires, and I usually just cut them off and use the wire. But I have toyed with the idea of leaving the little nobs on the ends of the plugs, and just plugging the automotive boots onto them.

This is what the wire set looks like...



The last set of these wires I bought were on close out at Rock Auto. I got the wire set for $3 and change, and even with shipping it was less than $10.