confused about plug wire

[drooker56]

What size plug wire do I need for this bike on stock coils? Does it matter the size if their not stock? Can I get this from an auto store? What about caps I am an electrical moran will any NGK cap do?

[DGXSER]

Well....first of all replacing the stock plug wires is not that simple. There is a tech tip on how to do it, but it aint for the faint fo heart as it requires dremeling holes in your coils and such.

As to the caps, I'll let soemone who knows more than I do comment, there is soemthign about resistance in the caps. But my brain does not want to pull it up right now.

[TopCatGr58]

Hey Rooker,

The stock coils do not have interchangeable wires, they were molded with the coils. THere's a tech tip that shows you how to put new wires into old coils, 7mm solid wire core type! The plug caps have a variety depending on what you want, resistor or not. Lately it's hard to find NON-resistor plugs now a days, so folks usually put on non-resistor caps and use resistor plugs. These resistors are just to cut out on radio frequency interference so your radio won't hum/whistle/whine with the engine running.

See the MODS Tech tips, electrical, and you should find the new wires in old coils tip and such!
T.C.

[Geezer]

The last time I replaced the wires on a set of stock coils, the glue was so weak I was able to tug the wires out. After that I dig out the remains out with a seal pick. Gluing in new wires was a snap...

Geezer

[dbeardslee]

Drooker - On a '79 your stock coils should have two long high tension wire tunnels with pins at the ends. They're a lot easier to change the wires on than the '81 coils. You can get the wires out by removing the outer sheath and then simply twisting and pulling on the high tension wire. Then dremel a hole close enough to the pin that you can tell when you've got the new wire on it (a little shot of WD-40 on the end of the new wire will make it go in a lot easier). Once you've got it all the way on the pin, put a zip tie around the outside of the coil and applying pressure to the new high tension wires - that'll keep them from backing out. As TC said, you need 7mm wires, and new plug caps are a good idea when changing your wires. On the older coils it's really very easy to graft the new wires in.

[drooker56]

Thanks a lot! can you get these 7mm wires at an auto store or are they motorcycle specific?

[dbeardslee]

Drooker - the one's I'm running are solid core wires I got from Smyth Automotive, locally. They say they're copper core, but I think they're really aluminum. They work great, and I just bought a cheap set for a four-banger cage. Cost me $12 and I got enough wire to do 2 1/2 rewires. Just make sure you get solid core wires and don't get resistor wires.

[oldyam80sg]

I got a set around 2 years ago and replaced 2 of the 4 wires in the coils.Very easy to do.The reason i didn't do the 2 inner coils is because i like the molded caps built into the wire and cant seem to find the correct angle.When i walk into an auto parts store and ask for a set they say which vehicle.i guess they don't understand that its going on a motorcycle.But there is alight at the end of the tunnel.Recently i found the local auto parts store tells me to bring in the wire and they will match it up with something.Once i get those wires i will do the inner wires.Looks sharp on the bike too.

[redbone]

yeah...follow the tech tip and measure with a volt/resistance meter and make sure your wires are bad. measure with the plug caps on and then with them off with the probe of the volt/resistance meter jammed into the end of the plug wire. maybe only the caps are bad.
[see tech tip about trimming plug wire 1/4 inch first]
fyi, mikesxs sells the proper caps.
like was mentioned...you will be hard pressed to find 'copper core' wire that is called for, best you will find is 'metal' [type unknown] core wire. i found an old auto parts store that still sold it off the spool for 31 cents afoot. cost me about $1.60 to do mine.
i used the bench grinder method to grind my wires out of the coil. not bad at all, just be CAREFUL not to grind the 'spike' off in the coil. suprisingly, i found rust on the spike when i did get the wires out. makes one wonder how moisture got in there to make that spike rust. anyway, good i did find it cause is cleaned it up and applied die grease and put it back together and sealed all with black RTV. works great.
hope this helps