Back to the Neon Coil mod (Again)

Information and questions on GL1200 Goldwings (1984-1987)
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Joined: Mon May 20, 2019 9:44 pm
Location: Grayson, Georgia
Motorcycle: 1985 GL1200I Interstate
1985 GL1200A Aspencade

Back to the Neon Coil mod (Again)

Post by TheRepoGuy »

I’m going to revisit this topic in the hopes SOMEONE might have an insight. I posted in a different forum about it but will here too. My CDI is cooked! The board was burnt and let out the magic smoke the other day and now she will run but only for a couple minutes before totally crapping out.

With the neon coils - Does it really make a difference if the resistors are removed from the plug caps? I’m thinking because the OE coils are a low ohm system I may need to add something in line to make or prevent this from happening again; OR it could have been the problem in the first place and someone replaced the coils without checking everything (or rebuilding in my case) first.

I like the setup with the neon coils but if it’s not gonna work like it should or it’s cooking my CDI box then it’s gonna be a trip back to the stock system.

Advice from the masses would be appreciated!

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Re: Back to the Neon Coil mod (Again)

Post by Rambozo »

Sounds like you toasted the output transistors in your CDI box. I've done that on bikes with coil problems, it's a pretty cheap and easy fix to replace them. Resistor caps are primarily for radio noise suppression, but they do act as a current limit, too. I don't know anything specific about the neon coil mod, so someone else can fill in the details but I would keep any resistors in place.

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Re: Back to the Neon Coil mod (Again)

Post by AZgl1800 »

DaveO430 kind instigated this mod, when he got tired of the OEM stuff burning up all the time. ... ost3932730

I just sent him a PM to replace the photos that are now blurred out by PhotoBucket.

'02 GL1800
2009 Piaggio MP3 250cc

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Re: Back to the Neon Coil mod (Again)

Post by DenverWinger »

The absence or presence of resistors in the secondary (sparkplug) side of the coils won't make any difference in the current load on the CDI box, but what CAN make a difference is the coil resistance on the primary side. A coil with too low a primary impedance could overload the CDI.

Wonder what's the resistance of the primary side of the Neon coils vs OEM....
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪ :shock:


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Joined: Wed Mar 12, 2014 1:56 pm
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Motorcycle: 1985 Goldwing Aspencade (GL1200A)
2002 GL1800

Former bikes;
2000 R1100RT
2005 Suzuki Bandit
1979 Yamaha XS1100
1978 Yamaha XS1100 Special
1990 Yamaha XV250
1980 Yamaha XV750
1979 Honda CB750
1968 Triumph Bonneville T120
1973 Honda CB450
1968 Harley Davidson Sportster
1974 Honda CB750
1968 Honda CL72

Re: Back to the Neon Coil mod (Again)

Post by froche »

I did this change out on my 1985 Gl1200A. The bike has started and run fine but only short rides so far.
Before the change out the bike started OK using the enrichener, and ran fine.
After the change out the bike started without the enrichener.
I did increase the plug gap to .40, was thinking about trying .45.
The old plugs were absolute fine as far as color, they could have been used to show perfect combustion!
One interesting note 1 plug was incorrectly gapped (or narrowed through use), cylinder 4 (right hand rear) was nearly .10 from suggested .35, and a little off on color.

Year ago I had a Ford 351 with Kettering ignition system in a Ford LTD, got about 12 miles to the gallon.

I put in:
Capacitance ignition (boosted the coil)
Electronic Conversion for the Points etc
Used metallic wires for Spark
Increased the gap by .10 until .70 still ran good

Mileage on the freeway went up to nearly 20 and around town around 16.

The whole point of this is to explain that when your voltage goes up you can;
Either leave stock gap and still work well in less than ideal conditions (oil in the combustion chamber, poor compression, non optimized gas mixture. leaner gas mixture)
Increase the gap, making the spark bigger and perhaps a tiny bit longer, and start the combustion better.

Interestingly there is a claim that manufacturers plug gaps are a bit conservative. After all they have to warranty their engines and cannot count on most people to keep them in a proper state of tune. Now with the introduction of Coil over plug, sensors replacing distributors and computers running the show they have been able to get closer to the exact gap for that engine. However for Kettering ignition system, and early non computer ones the over all cliam is that you can increase the gap by .10 over stock.

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