Iridium

[donebysunday]

plugs seem to only be available in resister type, in which case non-resister plug caps are needed.
Plug caps seem to only come with resisters ?
Anyone using the iridium plugs, ... did you find non-resister iridium plugs (got a part number?) or non-resister caps, (again a part number or where to find the non-resister caps ?).
I'm ready to just forget iridium plugs all together !

[3Phase]

They're only available in a black 90 ell and they only work with the aftermarket Iridium IX plugs with threaded, removable connectors like the stock plugs.

The Iridium OEM-style Laser plugs have solid connectors that can't be removed, you'd have to use some crimp-on automotive connectors and rubber boots on the plug wires to get rid of the resistor caps.


NGK 8381 (Black)

[CaptonZap]

Take the stock (resister type) cap apart by unscrewing the inner brass center piece. Inside is the resister element, which is a small cylindrical piece that looks like a short piece of ceramic rod. Find some copper tube or wire the same diameter, and cut it the same length as the resisters. Re assemble with the copper pieces, and try the iridiums. Save the resisters, in case you want to go back.

CZ

[3Phase]

The stock outer caps, Tokai-Denso T-134, can't be rebuilt like that. The brass terminal in the cap doesn't unscrew, it's pressed in like the steel screw for the plug wire.

I haven't opened one up yet but I'm pretty sure the resistor is in the body in-line with the steel screw and plug wire, not under the brass terminal.

[donebysunday]

Thanks guys !
I'll look, maybe the caps I have on the bike can be taken apart ?

[MPittma100]

Resistor

You will not have too much resistance using the resistor plug boot with the resistor plug. Resistance is there for RFI only. If you install the Iridium plug, no worries.

[donebysunday]

You will not have too much resistance using the resistor plug boot with the resistor plug. Resistance is there for RFI only. If you install the Iridium plug, no worries.

I thought that spark might be reduced with double resisters. What I did, ..... cut 1/8" off the wire and brand new NGK resister plug caps and brand new Iridium plugs with resisters (only way they come) just to try and get the best spark out of this combination as possible.
As I said I've had Iridium plugs foul out on me after only a couple months, thought it might be all the resistance .

PWSlawson from the XS650 list agrees.
Resistors main function in vehicles is noise suppression-radio interference. In olden times, generators caused a whistling noise in radios so a resistor was bolted to their cases. Alternators have them in their internal circuits. if you look at old (70”s) plug wires you’ll see them labeled “noise suppression” or something like that. Resistor plugs were developed because early high energy ignition systems caused radio and TV interference. I’ve seen guys put resistor plug wires, resistor plug caps, and resistor plugs on his bike and then wonder why it was hard to start and had no power. Lots of resistance causes weak spark. Use one type of resistor only. I prefer resistor plugs because I think solid plug wires and caps last longer and are more reliable.
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[IanDMacDonald]

I have Irridium in a few of my bikes, and will eventually go back to regular plugs. I never saw any plus to them.

[3Phase]

http://www.oreillyauto.com/site/c/de...381/N0944.oap?
NGK 8381 non-resistor caps

[donebysunday]

http://www.oreillyauto.com/site/c/de...381/N0944.oap?
NGK 8381 non-resistor caps

Scott, have you used these, looks like the shape would be fine for cylinders #1 ans #4 . I wonder if the caps are the right shape/length for #2 and #3 ?

[IanDMacDonald]

Scott, have you used these, looks like the shape would be fine for cylinders #1 ans #4 . I wonder if the caps are the right shape/length for #2 and #3 ?

I have 'em on all 4.

[Bonz]

Other than the theoretical issues with two resistance mechanisms in line for the spark, has there been a consistent (felt or seen) negative difference with an otherwise healthy ignition system?

The SG has had the same Iridium set for 6 years/just over 6,000 miles. About 1,000 good hard miles a year between a rally and a few longer day rides. Overall it does not get run stop-and-go or short hops.

Does it matter if the bike is run at lower speeds? Typically around town and lower RPM, since the charging system does not work as well at lower RPM could that be contributing to the problem with double resistance and not a good spark? Where as on the highway the charging system is putting out full power and therefore the battery is able to give a full spark and the double resistance is not a factor.

[3Phase]

Scott, have you used these, looks like the shape would be fine for cylinders #1 ans #4 . I wonder if the caps are the right shape/length for #2 and #3 ?

I have them on my XJ, all four plugs, no problem, they might not work if the wires have been trimmed too much on #1 and #4.

The shape makes them a hair more difficult to remove on #2 and #3 but nothing serious.

[donebysunday]

I have them on my XJ, all four plugs, no problem, they might not work if the wires have been trimmed too much on #1 and #4.

The shape makes them a hair more difficult to remove on #2 and #3 but nothing serious.

Checking with O'Reilly shortly, got the number 8381 .