??? - spark plug wires - what are you folks doing?

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joe czech

joe czech

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when I bought my 74 it came with a couple (new) moroso "blue max" 800 ohm custom fit spark plug wires. yesterday, I pulled them for a resistance check. one measured 770 ohms, which i'm assuming is correct since it about a foot long. the other measured 3.37K ohms, and I have no idea why the reading are that different. i'm running straight champion copper core plugs and tri-spark electronic ignition. with standard twin 6V coils.

anyway, i'd like to sort out the spark plug wires, so my question - what are you folks doing for spark plug wires? tried a little on-line research and i'm getting into information overload. i'm thinking resistive caps, either NGK or champion, and straight 7mm copper core wire - something like Packard 440, and crimping my own, or straight resistive spiral wound wire without 5K boots. I know you need some resistance, but how critical is the 5K ohm number? comments, comments, comments....
 
Seeing that resistor plugs are the currently stocked items in an auto parts store, I opt for solid core wires with no resistor cap and let the plug provide the resistance. 5K is the accepted standard but I don't think it's critical. A few hundred more ohms in the wire won't matter. I would be concerned however that one of your wires reads so much higher than the other. Perhaps an autopsy is in order.
 
Different manufacturers ask for different things.

Bear in mind the recent discovery of the Tri-Spark Classic Twin missing a beat at 3-4,000rpm when coupled to a Podtronics.
More info here: LINK
We know they have issues with this model, because it is this model that Tri-Spark sell, so this is what the tested against.
It may also happen with others.

Another example is Sparx:
In their electronic ignition instructions, they call for ‘5K resisted spark plug caps’ and state that failure to use them ‘will cause overloading’ AND ‘resisted spark plugs’, as circuitry is sensitive and failure to do so ‘will cause over charging’

Power Arc says:
Use ONLY Resistor (CARBON CORE) or Approved Spiral Wound Spark Plug Wires & Resistor Spark Plugs.

Pazon state:
Always use copper cored ht leads. Do not use carbon-fibre (resistive) leads.
We recommend fitting NGK 5K resistor (suppressor) type plug caps (or similar good quality make), but you can also fit non-resistor caps.


So many of these units are perhaps a little more susceptible to radio frequency interference (RFI) and electro-magnetic interference (EMI) than we first give them credit for.
It may be that silicon core and carbon core leads are better in many ways than the copper core ones that we have always opted for in the past.

I have no data or comparison info - this is purely thinking out loud based on what I have read lately.
 
It's not easy to find the copper leads that Pazon requires.
None of the local Autoparts suppliers stocked copper core plug leads.
One supplier was able to order in a copper cored ignition wire kit for a common V8 Chev 350 or similar.


Glen
 
worntorn said:
It's not easy to find the copper leads that Pazon requires.
None of the local Autoparts suppliers stocked copper core plug leads.
One supplier was able to order in a copper cored ignition wire kit for a common V8 Chev 350 or similar.


Glen
Click to expand...
I got mine from a hardware store, they're used on outdoor power equipment like lawn mowers. Also used on 2 stroke outboard marine engines.
 
gtiller said:
Different manufacturers ask for different things.

Bear in mind the recent discovery of the Tri-Spark Classic Twin missing a beat at 3-4,000rpm when coupled to a Podtronics.
More info here: LINK
We know they have issues with this model, because it is this model that Tri-Spark sell, so this is what the tested against.
It may also happen with others.

Another example is Sparx:
In their electronic ignition instructions, they call for ‘5K resisted spark plug caps’ and state that failure to use them ‘will cause overloading’ AND ‘resisted spark plugs’, as circuitry is sensitive and failure to do so ‘will cause over charging’

Power Arc says:
Use ONLY Resistor (CARBON CORE) or Approved Spiral Wound Spark Plug Wires & Resistor Spark Plugs.

Pazon state:
Always use copper cored ht leads. Do not use carbon-fibre (resistive) leads.
We recommend fitting NGK 5K resistor (suppressor) type plug caps (or similar good quality make), but you can also fit non-resistor caps.


So many of these units are perhaps a little more susceptible to radio frequency interference (RFI) and electro-magnetic interference (EMI) than we first give them credit for.
It may be that silicon core and carbon core leads are better in many ways than the copper core ones that we have always opted for in the past.

I have no data or comparison info - this is purely thinking out loud based on what I have read lately.
Click to expand...
thanks, thanks, thanks for posting the tri-spark/podtronics thing. not sure what model tri-spark I have, but i'm thinking it's an older unit - came with the bike along with the podtronics unit. can't recall I've notice any 3-4K RPM issues though. I kind of understand what they are trying to do with the capacitor filter, but off the top of my head, I would think they should run one end from unit input, and the other end of the cap to ground. probably don't understand the input/output of the device, but to me, looks like they're running it in series with the ground wire - ??? if anything I would think it should run parallel with the ground wire - again ??? might have to look into this a bit. i'll have to dig into the original paperwork that came with the tri-spark/podtronics.

I'd switch to resistor plugs, but I have a stockpile of N7YC's - probably enough to last me and the next owner's lifetime. hate to see them go to waste. most likely the best approach is resistor caps and copper core wires.

I can tell you with my current set-up - copper core plug, and my mis-matched moroso wires, i'm not experiencing any performance issues. the mis-matched wires initiated my concerns - somethings not right.
 
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The original Trispark Classic (round red thing with epoxy in the back) called for solid wires. I used one for 10 years with N7YC plugs and zero issues. The newer model (black epoxy on top and a test button) calls for 5K resistance caps or plugs. I've also used that with copper plugs and no issues, though now I've switched to resistor plugs just becuz. Interference with charging systems depends on wiring. My regulator is back in the battery compartment a long way from anything sparking and I have not seen overcharging.
 
Pick your wire and end pieces and make your own.
??? - spark plug wires - what are you folks doing?
 
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now it shows....

so I have to ask, it that some sort of kit or just random pieces/parts sold on fleabay.
 
I’m rather new to the old bike scene, and, not knowing any better, when I recommissioned my 74 I simply used solid copper wire leads, along with NGK plugs, non-resistor. This then caused my ICM battery warning light thingy to play up, I was advised by the seller to use 5k ohm resistor plug caps. This cured it. I believe if I’d used resistor plugs then normal caps would have been needed. I also changed the cables as the first ones I purchased were a straight fitting into the coil and I’m not convinced that I was having misfiring issues as a consequence of them being so close to the rocker covers. I’ve changed the leads for a pair where they come out of the coil at a right angle, and a nice curve to the plug.
 
Talyor wire and 90* metal plug ends and 90* metal coil ends from Taylor. Acell Supression wire left over from a truck project. Acell SS core wire (not shown) w/ Acell plug boots are Harley parts. Champion silicone plug boots were from Feked. Crimper might have been an Amazon item. Basically sourced up parts when I needed them for various projects

Edit: Spelling correction
 
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Anyone have a source for the original type Champion plug boots (black rubber) for the late 750 and 850 Commando? These are not the ones Deets55 show from Feked.
 
Ron L said:
Anyone have a source for the original type Champion plug boots (black rubber) for the late 750 and 850 Commando? These are not the ones Deets55 show from Feked.
Click to expand...
Hi Ron,
No, but those original plug caps were not that nice. Just a rubber cover that went over the wire and metal contact clip. I like the caps that have a sheet metal thread that screws into the wire core.
 
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