Resistor caps/resistor plugs?

[Armen]

Does the stock ignition on a '98 900SS need to use resistor plugs or caps? On some of my bikes they needed a resistor cap, others ran better with non-resistor stuff. I could swap out to an NGK non-resistor cap and I have NGK non-reisistor plugs. Might not be an issue, but on some HDs and BMWs the ignitions are so marginal that a non-resistor plug helps.
thanks,
-Armen

[Joe-B]

Non-resistor. I read somewhere that a non-resistor plug is worth about 1 1/2hp (Shazaam?).

[Shazaam]

It is strongly recommended that resistor spark plugs be used in any motor that has an on-board computer system that is used to monitor or control engine performance. Use of a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects (caused by electromagnetic interference) such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion.

Resistor wires alone often can't provide the necessary noise suppression. When they are combined with resistor spark plugs, the level of interference is greatly reduced.

Using resistor plugs does not affect engine performance. Starting, acceleration, fuel consumption, and exhaust emission characteristics are identical to those produced by non-resistor spark plugs.

Ducati Ignition Systems

[Armen]

I'd hesitate to call the ignition system on a carbie 900SS a 'computer'.
I do remember a few years ago when Motorcycle Consumer News ran a carbie Sportster with reisistor and non-resistor plugs and picked up 1 HP with the non-resistor plugs. Prob a statement as to how dickless the HD ignition is.
I know on the electronic ignition BMW Airheads they have to run resistor caps, but are happier with non-resistor plugs.
Hence the question.

[Joe-B]

I don't think Shazaam read your post too well. No computer on a 1998 SS! I have never put a resistor plug in my track bike in 30,000 miles and the motor seems to like the non-resistor plugs just fine. I found where I read that they produce more hp:
"Chris (Kelley; Ca-Cycleworks) prefers a non-resistor plug as using resistor plugs has been proven to reduce output by 1-2 horsepower."
Evidently he does not agree with Shazaam. This is referring to the NGK D8EA non-resistor plug he sells (and prefers for non-computerized Ducatis).

NGK D8EA Non-Resistor Spark Plug NG2120 | Electrical / Ignition | Products | ca-cycleworks.com

[Shazaam]

I suppose you can argue that a carb bike doesn't NEED a resistor type spark plug, that is, if you don't mind pissing-off the guy next to you on the freeway who's trying to listen to his radio.

Chris Kelley at CA-Cycleworks is a knowledgable and trusted vendor who says he prefers a non-resistor plug that has been "proven" to increase output by 1-2 horsepower. The plug manufacturers claim there's no difference in power output, and I since can't find any supporting evidence, just help me out here, where's the proof?

[MitchB]

The plugs thing -I kinda get. A spark is a spark...
Before I backed a resistor type over non, I'd want to see back-to-back Dyno runs on same bike, same temp plug, SAME plug GAP. Or adjust the gap a smidge to see if the 1-2 HP came back... 1-2 HP is almost "gauge error" on a 200HP+ capable dyno...

My question is about wires...
I have a couple of sets (for my '81 Darmah (early Bosch) and my carby 900SS) of wires:

One is a normal looking red with twisted wire core (NGK Racing Cable IX),
One is a red Magnecore (KV85 "EMI Surpressed Conductor")with a rubbery core,
and, a black 7mm "no name" High Temp with "conductive Silicone Core" that I got from a Vintage Ducati source...

I'm relatively certain the wire core is non resistor..

Are resistance wires / Caps / Plugs needed ONLY for reduced electronic interference? Won't the resistance affect other components - i.e., coil output / input? I've read (we all know the Internet never lies..) that the wrong wire can harm the ignition box / coils / condensors, etc. Can someone tell me which is best for which application and why..?

[Joe-B]

Originally Posted by Shazaam

I suppose you can argue that a carb bike doesn't NEED a resistor type spark plug, that is, if you don't mind pissing-off the guy next to you on the freeway who's trying to listen to his radio.

Chris Kelley at CA-Cycleworks is a knowledgable and trusted vendor who says he prefers a non-resistor plug that has been "proven" to increase output by 1-2 horsepower. The plug manufacturers claim there's no difference in power output, and I since can't find any supporting evidence, just help me out here, where's the proof?

Good question...

[Armen]

This is one of those many things I'd like to try out on a dyno. if only I had unlimited time and dyno access : (

[Punch]

Originally Posted by Shazaam

I suppose you can argue that a carb bike doesn't NEED a resistor type spark plug, that is, if you don't mind pissing-off the guy next to you on the freeway who's trying to listen to his radio.

Chris Kelley at CA-Cycleworks is a knowledgable and trusted vendor who says he prefers a non-resistor plug that has been "proven" to increase output by 1-2 horsepower. The plug manufacturers claim there's no difference in power output, and I since can't find any supporting evidence, just help me out here, where's the proof?

Radio - agree wholeheartedly.

1 -2 HP - It would be interesting to see variations in dyno runs with the same plugs over multiple runs. 1 to 2 HP in say 80 is 1.25 to 2.5% accuracy - what do dyno manufacturers claim?

I don't ride flat out so torque is of more interest to me.

Plug manufacturers - this is their life/business, plus compliance with EMI regs, so I would be inclined to believe them. Until you see many dyno runs to eliminate/average reading errors, you won't really know - statistics, statistics and damned lies as someone more clever than I once penned.