Neon Spark Plug wires

[Tom]

Mike,

What is the deal with the neon spark plug wires you see on the chopper shows? Any performance or just cosmetic. Also, I read they make the check engine light go off on Harleys, is this true and will it fling fault codes? Do they hurt the bike? Thanks.

Tom

[Mike]

They are only for show but do look cool at night. There is an argument that they hurt performance by reducing spark energy. We've not been able to confirm this, but I have known them to simply fall apart and leave people stranded. As far as damaging the bike, probably not but stray sparks near the gas tank (when they break apart) would bother me.
On EFI bikes, anything that changes the resistance in the spark plugs or cables can potentially cause "no combustion" codes as a function of the Ion sensing anti-knock control. We've seen aftermarket cables and plugs actually do this! :o
Regards, Mike

[Tom]

Thanks Mike,
Now if they do fling codes to the computer, will these codes cause a shutdown of the bike or change fuel mapping on EFI models?

[Mike]

If codes are thrown, due to the neon cables, they will typically be of a historic nature (light comes on when the bike is started but goes out after a few moments) and do not affect or alter how the bike runs. If a current code (light comes on when the engine is started and stays on) should occur, this would indicate that something's wrong and may be associated with running issues, but these running issues would be a function of the actual problem not the engine code. I.E. an engine light itself does not alter how a bike runs and clearing engine lights do not restore or reset the ECM. We just lose the information that caused the light to set.
Regards, Mike

[Tom]

Ok now I've done it, I bought neon wires. The instructions are asking me to install the bracket that holds them to a 1/2" bold dead center under the jugs. Question to you mike, what is that bolt there for and before I remove it, I want to make sure it isnt supporting something in the engine. This is on left side of bike, dead in center of the jugs where they connect to the case. 1/2" . Thanks.

tom

Disregard the last post, the bolt is the center bolt that holds the cases together, no way am I mounting to that, I am mounting to the horn bracket instead. Sorry!!

[Mike]

Cool

[Tom]

Just wanted to report, I see no loss of anything using the neon wires. I did install so I can revert to stock wires in 2 minutes or less. They do look cool at night, but during the day, useless. : )

[Mike]

I appreciate the report. Be it night or day, looking cool is always important!
Mike :)