replacing spark plug wires

[oldgsfan]

The wires leading to my spark plugs have big old cracks in them just before the boot that goes on the spark plug. So I was thinking of replacing them.

I'm not noticing any problems, it just seems like it would be a good idea to install some new wires and, I figured, new boots at the same time.

I've read several posts on spark plug wire replacement, but I'm confused as to what I need to know before purchasing, much less replacing, what I already have on the bike.

Z1 sells what they describe as Dyna ignition wires, 7mm suppression core wires. So, would those work? It also warns against using these wires with "resister plug caps." I don't understand what that means. How do I know if I have resister plug caps?

I'm really weak when it comes to electronics.

 

[JEEPRUSTY]

The wires leading to my spark plugs have big old cracks in them just before the boot that goes on the spark plug. So I was thinking of replacing them.

I'm not noticing any problems, it just seems like it would be a good idea to install some new wires and, I figured, new boots at the same time.

I've read several posts on spark plug wire replacement, but I'm confused as to what I need to know before purchasing, much less replacing, what I already have on the bike.

Z1 sells what they describe as Dyna ignition wires, 7mm suppression core wires. So, would those work? It also warns against using these wires with "resister plug caps." I don't understand what that means. How do I know if I have resister plug caps?

I'm really weak when it comes to electronics.

Is it the wire that is cracked or simply the protective sheathing?
My sheathing is a bit nasty looking but the wires are fine.

Had te replace caps but that is another story.

 

[oldgsfan]

Sorry, I should have been more clear. It's the protective sheathing, the rubber, that's cracked, not the wire itself, at least not as far as I can tell.

 

[raistian77]

If you do end up replacing the wires its pretty easy, I went to Advance Auto and bought a box of Accell P/N 3008 spoid core wires.

http://www.thegsresources.com/_forum/showthread.php?t=164554

 

[Redman]

About the caps:
THe stock type and typical motorcycle caps (NKG ectera) have resistors of about 5K ohms (sometimes called supressor, I quess is to suppress radio interference).

For some reason automotive has the resistance built into the materail of the wire (wire, the conductor, the wire wire), and not in the caps. WHich seems strange to me since one wire length is different than the other. But anyway....

So if you use automitve wire you will want to use automotive caps.
If you use automotive wire and mo'cycle caps than you get more resistance than you need.

Other commnent:
- the wire is ment to come out of the cap. The cap has a threaded pointy thing that can unscrew/screw the wire off from / on to.
- the wire really isnt ment to come out of the coil. BUt have seen that can dig the wire out of the coil, with some difficulty that someone other than me can tell you about.

.

 

[Wallowgreen]

If you do end up replacing the wires its pretty easy, I went to Advance Auto and bought a box of Accell P/N 3008 spoid core wires.

http://www.thegsresources.com/_forum/showthread.php?t=164554

I've done this on my '79 850. There are resistors in the plug caps and you can access them by using a fairly large flat blade screwdriver on the brass nut up inside the cap that clips onto the top of the plug itself. It just unscrews as normal tip it up and the resistor will fall out. They look like a white cyliner with metal ends and they should be 5k ohms.

It's pretty easy to cut away at the goop around the base of the wire where it goes into the coil, I used an xacto knife. After that dig away down into the coil body between the wire and coil, there is goop in there also. Once cleaned out the wire will pull off the spike you'll find at the bottom. Simply measure new solid core wire to the correct length and slide it down onto the spike. Look at the very familiar looking pictures shown in the link above. They were taken by some wierdo through a microscope. I put a small bead of high temp RTV around the wire about 1/4" from the end so that got smooshed up the recess in the coil body as the wire went in. Then a bead around where the top surface to support the wire and it's done.

The plug caps screw on and off, think I got mine from Z1. Have GKN type anyway.

I used the solid core wire available at NAPA, cost about 45c per foot IIRC.

 

[Guest]

What ill effects will be caused by using both resister caps and wires, if any?
I've asked this before but have yet to get a straight forward answer.

 

[JEEPRUSTY]

What ill effects will be caused by using both resister caps and wires, if any?
I've asked this before but have yet to get a straight forward answer.

i asked this too is the effect cumulative?
does 5k in the plugs get added to the resistance of the plugs or is the point of max resistantce the total for a circuit?

 

[Wallowgreen]

Well I went through this trying to track down why my 850 was running like crap. Though others know better than me, I suspect weak or poor spark will be the problem with sub optimal resistance in the coil secondary side. The system was designed to have a certain resistance from plug cap to plug cap for each coil. The secondary in each coil should read around 15k ohms and with 5k ohms in each plug cap you can read from plug cap to plug cap and get around 25k ohms.

I don't think these machines are smart enough to figure out whether the secondary resistance they see is in the plug cap or in the wire but the total needs to be right I reckon.

Personally, I didn't see the need to modify from the stock design so I went with resistor plug caps and solid core wire.

 

[oldgsfan]

About the caps:
THe stock type and typical motorcycle caps (NKG ectera) have resistors of about 5K ohms (sometimes called supressor, I quess is to suppress radio interference).

For some reason automotive has the resistance built into the materail of the wire (wire, the conductor, the wire wire), and not in the caps. WHich seems strange to me since one wire length is different than the other. But anyway....

So if you use automitve wire you will want to use automotive caps.
If you use automotive wire and mo'cycle caps than you get more resistance than you need.

Other commnent:
- the wire is ment to come out of the cap. The cap has a threaded pointy thing that can unscrew/screw the wire off from / on to.
- the wire really isnt ment to come out of the coil. BUt have seen that can dig the wire out of the coil, with some difficulty that someone other than me can tell you about.

.

OK. I think I've got it now.. I'm planning to get my wire and caps from Z1, so they'll be motorcycle wire and caps. And I'll follow the tips on the other thread about attaching them to the coil.

I've been wanting to replace them since I got the bike, and just haven't gotten around to it. The cords are cracked and it unnerves me.