How many millimeters are the plug wires we use? Does the size make a difference?

 

I think the stock ones are 8mm but I could be wrong. The size really only matters if the wires are longer. For our short wires it doesnt play a big of part in it.

I have the 10mm screaming eagle plug wires.

 

mine are 8mm, i went by color.... Not the size LOL. Of course my engine is pretty much stock also.

 

Stock wires are 7mm. I have 8mm wires with Iridium plugs. Much better spark with better plugs and larger wires!

 

Almost all the stock wires are 8mm. Like was said before, if the length is under 12" or so, it doesn't make that much of a difference. The bigger diameter is just more insulation, which leads to a stronger spark because the voltage leak-off is not as much.

For the average rider, it's not a big difference. If you want the peak power and performance, you can get some better ones.

 

Stock wires are 8mm
Most Screamin' Eagle wires are 10mm
Some of the older SE Wires are 8mm
PRO RACE wires are 10.4mm

The core of the wire and then the connectors are probably the most important factors in getting good spark.

I have noticed a difference in going from stock wires to the SE or Pro Race, BUT in each case it was from USED stock to NEW SE or PRO RACE. Wire core, connections and insulation all degrade with time, resulting in a weaker spark.

The all USA made Taylor PRO RACE will take longer to degrade than the stock or SE wires.

 

I have the SE 10mm wires and they seem to work great and look cooler than the tiny stock wires.

 

I swapped out plugs and wires from stock to SE on my '11 103 RG and it didn't idle as well?
The HD mechanic told me the internal resistance was different and the motor was designed and tuned with the stock stuff.
So what is the story on differences in the resistance here and am I just blowing money for nothing more appearances?

 

I got Hi 4N ignition and the 3 ohm coil looks stock. Got lost replacing the spark plug wires with ones with a 90 degree angle plugging into the coil. That looked nice. It did not last. Had to check the ignition to see why the engine would not run right. It is just that while checking the ignition top dead centre the spark plugs got pulled. It helped find the problem when the plug that goes into the coil came off the wire. I got to decide which way to plug into the coil.

 

I got some Taylor wires after one of the plug connectors in my SE wires separated, and repairs were futile. I like the Taylor plug connector much better than the SE. Plus it rocks in purple!

John