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1982 Sportster Electronic Ignition Help

Started by vafatboy1, April 03, 2021, 04:33:24 AM

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vafatboy1

My son's boss gave him a 1982 sportster.  Around 10 years ago a friend of mine got this sportster running for my son's boss.  In that 10 years the boss for some godforsaken reason took stuff apart again. 

When my son got it,it appeared to set up for points.  One wire from the cone to the what I think is positive side of coil (common to harness red wire landed on coil).  Installed and static timed electronic ignition.  New compufire elite 1.  I assumed stock setup to be dual fire, single plug.  4 wires on ignition harness.  Green and white not used.  Red to + on coil and black to - on coil.  When wired this way when starter button is pushed...nada.  When black wire is removed from - coil, I get starter circuit back.  When turning over the trigger illuminates ignition LED, but I have no spark. 

Hoping I haven't fried the ignition.  Any guidance is appreciated 

Tynker

When using points, the black wire from points goes to the negative - side of the coil.
Earl "Tynker" Riviere

vafatboy1

Quote from: Tynker on April 03, 2021, 06:50:32 AM
When using points, the black wire from points goes to the negative - side of the coil.

Understood and agrees with what I've read.  I'm using electronic ignition.

Tacocaster

I'm likely wrong but, I took a look at the wiring for a Compufire Elite 1 and don't think you have it quite right - but I likely misunderstood your description and photo.

The Compufire is looking for 12 VDC on its WHITE wire coming from the Coil's positive terminal (there should be 12 VDC from bike's harness already wired to positive terminal of coil).

The Compufire's PINK wire should be connected to the coils negative terminal. There is no other connection/wire on the coil's negative terminal.

The Green wire goes to your Tach (if you have one) and the VIOLET is for the VOES (if you have one) and the BLUE is not used.
We're all A-holes. It's to what degree that makes us different.

rigidthumper

Quote from: vafatboy1 on April 03, 2021, 04:33:24 AM
My son's boss gave him a 1982 sportster.  Around 10 years ago a friend of mine got this sportster running for my son's boss.  In that 10 years the boss for some godforsaken reason took stuff apart again. 

When my son got it, it appeared to set up for points.  One wire from the cone to the what I think is positive side of coil (common to harness red wire landed on coil).  Installed and static timed electronic ignition.  New compufire elite 1.  I assumed stock setup to be dual fire, single plug.  4 wires on ignition harness.  Green and white not used.  Red to + on coil and black to - on coil.  When wired this way when starter button is pushed...nada.  When black wire is removed from - coil, I get starter circuit back.  When turning over the trigger illuminates ignition LED, but I have no spark. 

Hoping I haven't fried the ignition.  Any guidance is appreciated 
Primary side of the coil is in line. Power to one side of the coil, other side of the coil to the arm of the points, body of the points to ground. Remove all factory wiring from the coil, and determine which is switched power, and if you have a tach.
The  Compufire unit is just an electronic version of the points. My understanding of their instructions, with 4 wires,  Green (VOES), Red (power), White (second coil trigger) and Black (first coil trigger). White wire is taped up, not used. Green isn't used unless you add a VOES.  Red wire goes on the positive side of the coil, joining switched power from the bikes harness.  Black wire goes to the negative side of the coil, joining a pink wire (if the bike had a tach originally). The body of the unit grounds through the metal housing. These units are robust, but can be damaged/fail if wired backwards.




HTH
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

vafatboy1

Quote from: rigidthumper on April 04, 2021, 06:15:37 AM
Quote from: vafatboy1 on April 03, 2021, 04:33:24 AM
My son's boss gave him a 1982 sportster.  Around 10 years ago a friend of mine got this sportster running for my son's boss.  In that 10 years the boss for some godforsaken reason took stuff apart again. 

When my son got it, it appeared to set up for points.  One wire from the cone to the what I think is positive side of coil (common to harness red wire landed on coil).  Installed and static timed electronic ignition.  New compufire elite 1.  I assumed stock setup to be dual fire, single plug.  4 wires on ignition harness.  Green and white not used.  Red to + on coil and black to - on coil.  When wired this way when starter button is pushed...nada.  When black wire is removed from - coil, I get starter circuit back.  When turning over the trigger illuminates ignition LED, but I have no spark. 

Hoping I haven't fried the ignition.  Any guidance is appreciated 
Primary side of the coil is in line. Power to one side of the coil, other side of the coil to the arm of the points, body of the points to ground. Remove all factory wiring from the coil, and determine which is switched power, and if you have a tach.
The  Compufire unit is just an electronic version of the points. My understanding of their instructions, with 4 wires,  Green (VOES), Red (power), White (second coil trigger) and Black (first coil trigger). White wire is taped up, not used. Green isn't used unless you add a VOES.  Red wire goes on the positive side of the coil, joining switched power from the bikes harness.  Black wire goes to the negative side of the coil, joining a pink wire (if the bike had a tach originally). The body of the unit grounds through the metal housing. These units are robust, but can be damaged/fail if wired backwards.




HTH

Thanks for this.  Got fire on starting fluid.   Chasing fuel now.  S&S Super B.

vafatboy1

Got fuel and spark, sort of.   Ran rough.  Checked spark on rear cylinder and no joy.  Problem chased when plugs switched.  Got new plugs and ran better.....but weak spark at rear compared to front.  Broke out the multimeter and resistance started at 4.5 and over a few seconds it dropped to 2.4-ish.  It would drift around a few points.  Sone went and bought a new aftermarket. 

We'll see how that works out. 

I could hear the rear cylinder firing intermittently.  It also didn't run as hot as the front. 


JW113

2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

xlfan

At about 25 years ago, we used to replace those rather big Super B suckers with Mikuni 38's for driveability.

My guess would be that a massaged Keihin of the era would be great as well.