NGK spark caps?

Hi all.

Looking to upgrade my ignition system.
I’ve looked on NGKs website for the ends that I would need on my 76 kz400 and they’ve got nothing listed.

I’ve read plenty of posts about people using them, however not listing which ones. Could anyone advise?

The spark plug cap depends on the plug wire and spark plug type you intend to use. My understanding is to have no more than one resistor component between the ignition coil and cylinder head.

Currently, my ignition setup has Dynatek non-resistor copper-core plug wires with NGK resistor caps, and non-resistor spark plugs.
I'm hoping to use a set of Taylor Resistor Core and TCW Wire Core spark plug wires. I assume they will need to be used with non-resistor spark plugs, but am uncertain about that.

Daveo speaks the truth. Too much resistance will cause arcing internally in the coil. My old kaw uses copper wires with >0< resistance, non resistor plugs, and caps with 5K ohm resistance. Keep in mind that this is a waste spark system. Sooo.. 5K ohms on one plug = 10K ohms secondary resistance on the waste spark coil (2 plug wires).
(I sent these mangled caps missing the rubbers back to the fleabay seller. BTW)


I am still running the original 40 year old coils. I will line my bike up against most anything modern on the roads today, and I often do for the 100 hp therapy.


If you are looking to "improve" anything, try some brand new OEM type components. Plugs, wires etc.. You really won't gain anything performance wise on a small 37 hp bike by "upgrading" anything, but you can cause all kinds of expensive problems by installing the wrong parts.

A google search shows Dynatek recommends using suppression core plug wires with the 2000 ignition system. So I wonder if Taylor resistor core wires will work better than copper core wires/res-caps I've been using since 2012.

:whistle:

daveo wrote: A google search shows Dynatek recommends using suppression core plug wires with the 2000 ignition system. So I wonder if Taylor resistor core wires will work better than copper core wires/res-caps I've been using since 2012. :whistle:

Obviously the resistor caps are working Dave. The suppressor wire is ohms per ft. Longer wire has more impedance. The caps are a fixed resistance. Your bike, your call, Your money.

You only need resistance on one of the components if you have electronic ignition. If you have points you don't need any of the components to have resistance.
The only reason points systems had resistor caps back in the analogue days is so that there was no chance of interferrance with domestic tv's and radio's etc. As they are all digital now there is no requirement or reason for it.
Why impede the flow of electricity to the spark plug when you don't need to?

While warren makes a valid point about emi / rfi affecting radio's and TV's, it can also cause havoc with other systems too. Particularly computers, electronic ignitions and automotive electronics. I also try not to re-engineer the coil primary or secondary impedance.ignition design specifications, which has it's own cause and effects, such as burnt coils and ignition modules. I still have working original components except new wires and caps and OEM ngk plugs. My bike will zing to red line without a blip. No spitting, sputtering, popping, missing, nada. Your mileage may vary.

This is a copy / paste by Bodi from the SOHC / 4 site with some insight into the copper vs resistor wires.

Secondary (the spark plug part) resistance shouldn't affect the points. The secondary resistance reduces the peak spark current and extends the spark duration but has little effect on the primary circuit. Reduced spark amperage reduces the electromagnetic energy pulse produced, this reduces interference in nearby AM radios. Having no resistance in the plug circuit can produce enough interference to cause problems with bike electronics as well, electronic ignitions in particular.
The extended spark duration should make for better mixture ignition as well. You shouldn't run all copper wire without resistor plugs or caps. Using resistor caps, resistor plugs, and graphite core resistor wire is not a good plan either. I suggest either resistor plugs OR resistor caps and copper plug wires. Non-resistor plugs can be hard to find, so the idea of using the molded cap wires from a tractor or other vehicle 4-cyl metal core plug wire set and resistor plugs has some merit. Attaching the coils is difficult with the hardwired stock coils, but other compatible Honda bike coils have re-usable coil connectors and Dyna coils use standard automotive coil connectors.

forums.sohc4.net/index.php?topic=113607.0

I slightly disagree with the secondary not affecting the primary circuit. A coil is a transformer like any other transformer. Power in = power out.

Read the second post.. problems with an LED tailight? I suspect other problems may be causing that. lol

old_kaw wrote: it can also cause havoc with other systems too. Particularly computers, electronic ignitions and automotive electronics.

Leaving a trail of broken down cars in my wake is good with me, get back to 1970's clear roads!
As an added bonus it also interferred with police radio's!:laugh: