[mrtwowheel]

I just pulled spark plug caps and one went spinning around, not enough wire to cut the wire and refit the cap. Time to inspect and or replace coils, wires and caps. I may do the relay mod for the coils too.

OK, the wire is 7mm and must be metallic core. The stock caps are NGK 5000 ohm resistor types. The plugs are also resistor types. Why are there two resistor components? Wouldn't I have a stronger ignition by eliminating one of these resistors? Resistor cap with non-resistor plug or non- resistor cap with resistor plug, wouldn't that be better?

Scott

 

[glhonda]

Boy, for someone that has all the answers, you sure ask a lot of questions.......
There are "noise suppression standards" that limit EM interference and radio frequency interference. These can inhibit the operation of electronic devices.
Sometimes, the resistor in the plug doesn't meet the requirements, so a resistor cap is used. Probably because we are not using suppression wire.
What coil mod?

 

[mrtwowheel]

Boy, for someone that has all the answers, you sure ask a lot of questions.......
There are "noise suppression standards" that limit EM interference and radio frequency interference. These can inhibit the operation of electronic devices.
Sometimes, the resistor in the plug doesn't meet the requirements, so a resistor cap is used. Probably because we are not using suppression wire.
What coil mod?

Yes, there may be some electronics on these bikes that require more resistance.

Coil mod, I just did this on my CB 750 Custom. A relay ( 5 pin, horn type ) is used to get more voltage to the coil, voltage that is lost through the ignition switch, kill switch and old connectors. The coil primary power wire is disconnected from both coils and connected to one terminal on the relay to be used as a trigger to connect battery power directly to the coils resulting in more voltage to the coils. All other functions on the bike work as before.

One relay $10, one fuse and holder, some wire and a few well soldered connectors. Well worth the money and time spent.

Scott

 

[glhonda]

Why do your coils need more voltage? Are they misfiring?

 

[mrtwowheel]

Why do your coils need more voltage? Are they misfiring?

No (emoticon inserted here), 27+ year old bike? (2nd emoticon goes here)

Scott

 

[oldishwinger]

I would humbly suggest that resistor plugs may not be needed, but resistor caps, are.

On my 86 aspy, I have iridium plugs, with no resistors, but the caps do. I have no interference on on radio, cb etc.

 

[Cornpone]

I would humbly suggest that resistor plugs may not be needed, but resistor caps, are.

On my 86 aspy, I have iridium plugs, with no resistors, but the caps do. I have no interference on on radio, cb etc.

Not to hijack this thread, but how do you like those iridiums?

 

[neoracer]

i run Taylor Spiro Pro 7mm wires which get rid of the NGK caps and still have good RFI ability,only have approximately .8K resistance which relates to a better spark at the plugs and doesn't bother radio or cb at all,been running these for more than 4 years and both my SEI and Aspy,plus they have molded 45 deg sparkplugs boots,used the same style wires on my racecar with a mag for years

Taylor Cable 73253 - Taylor Spiro-Pro Spark Plug Wire Sets - Overview - SummitRacing.com

 

[Ansimp]

No (emoticon inserted here), 27+ year old bike? (2nd emoticon goes here)

Scott

The 27 year old ignition switch is the real problem, lower voltage means weaker spark which may not misfire until the plug gaps get too wide. Better quality spark will help with more complete burning of the fuel so a relay mod may put money in your pocket

 

[mrtwowheel]

The 27 year old ignition switch is the real problem, lower voltage means weaker spark which may not misfire until the plug gaps get too wide. Better quality spark will help with more complete burning of the fuel so a relay mod may put money in your pocket

Yeah that. Longer plug life, easier starts when cold too.

Scott

 

[redwing52]

Higher resistance forces the coils to create more energy (voltage) and that will give a bigger spark. Did you ever have a fouled plug and it would not run on that cylinder. Then pull the plug wire off (increasing resistance) slightly to make it fire? By pulling the wire off it forced the coils to make more voltage and the "hotter" spark fired the fouled plug. By going with lower resistance the spark (voltage) will decrease. If you have a fouled plug you can spot it with a scope as it has a real low spike. Low resistance and low voltage.

 

[mrtwowheel]

Higher resistance forces the coils to create more energy (voltage) and that will give a bigger spark. Did you ever have a fouled plug and it would not run on that cylinder. Then pull the plug wire off (increasing resistance) slightly to make it fire? By pulling the wire off it forced the coils to make more voltage and the "hotter" spark fired the fouled plug. By going with lower resistance the spark (voltage) will decrease. If you have a fouled plug you can spot it with a scope as it has a real low spike. Low resistance and low voltage.

I have to differ with that comment. The coil is a transformer and the voltage that it puts out is related to the voltage that goes in.

Scott

 

[glhonda]

I have to differ with that comment. The coil is a transformer and the voltage that it puts out is related to the voltage that goes in.

Scott

The strength of the voltage going in has no affect other than by design. The amount of voltage that comes out is determined the strength of the field and the number of windings it "cuts" when it collapses.
Redwing is correct. The coil seldom operates at full capacity unless the wire and/or plug has gone open.
Scope an engine, remove the plug wire and watch the voltage line spike high.
Again, if you have no driveability issues, there is no need to modify your ignition. I get 42-44 mpg, no start or drive complaints, and I change my plugs every15,000 miles. Standard NGK factory heat range.