1986 GL1200A Spark Issue


Information and questions on GL1200 Goldwings (1984-1987)
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monstermatt
Posts: 3
Joined: Thu Jul 28, 2011 3:15 pm
Location: Bryan
Motorcycle: 86 GL1200A

1986 GL1200A Spark Issue

Postby monstermatt » Tue Jan 03, 2012 1:53 pm



I have GL1200A that I haven't driven in about 3 months and now I have spark issues (it's not the kill switch). In the fall it ran great and I had no issues with start up, idle, nor riding. The other day I went to start it and the battery was a little weak so I hooked up some jumper cables. It cranked fine but wouldn't start. Turns out I have no spark. I pulled the plugs cleaned them and still nothing. I can hold them in my hand and nothing. I checked, I have power going to the ICU, into and out of the coils but nothing coming out the spark plug wires. When I crank engine with a multitester at the coils it shows that the current is pulsing into and out of the coil. I haven't tested the coils yet, but I'm not sure how both could go out at the same time. Does anyone have any ideas what's going on? Does anyone know what the voltage level at the coils should be? If the current is pulsing into the coil then the pulse generator is still working right? I'm pretty puzzled by this one...



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virgilmobile
Posts: 7655
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: 1986 GL1200A Spark Issue

Postby virgilmobile » Tue Jan 03, 2012 3:21 pm

I'm gonna take a wild guess at this one...Let's see..the secondary winding is about 12,000 ohms and the primary is 3 ohms,so there is a 4000 to 1 winding ratio..If you pulse 1 volt in,you get 4000 volts out.
OK,not exactly,but with that info,to get a 40,000 volt spark you would need a good 10 volt pulse with a lot of current.
Just remember that this is a very very very short duration pulse and usually can't be measured with a analog or digital meter.When I suspect a coil,I will use an oscilloscope or sub another coil.Even a automotive coil will due,as long as the primary winding is very close to the same resistance as the bike.

Also remember,If you pull both plug wires and only hook up one plug to it,the plug will not spark.It requires both plugs attached to each coil to complete the spark circuit.It sparks 2 plugs at a time.

It is possible that jumping the bike may have damaged the ICU where now it doesn't provide enough power in the pulse to the coil to fire off the spark.
*****Other than the voltage requirement during cranking***** there are only 3 pieces involved..2 pulse coils,the ICU , and the ignition coils.
IF it applies to your bike,here's a schematic.

monstermatt
Posts: 3
Joined: Thu Jul 28, 2011 3:15 pm
Location: Bryan
Motorcycle: 86 GL1200A

Re: 1986 GL1200A Spark Issue

Postby monstermatt » Tue Jan 03, 2012 8:10 pm

I've checked pretty much everything. It looks like it's either the coils or ICU. I'm going to pull the coils tomorrow. Hopefully it's them since they're much cheaper.

User avatar
virgilmobile
Posts: 7655
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: 1986 GL1200A Spark Issue

Postby virgilmobile » Tue Jan 03, 2012 9:39 pm

You should be able to check the coils without pulling them.the primary measures about 3 ohm and the secondary around 12K ohm(between the 2 plug wires).No resistance should be measured to ground.

monstermatt
Posts: 3
Joined: Thu Jul 28, 2011 3:15 pm
Location: Bryan
Motorcycle: 86 GL1200A

Re: 1986 GL1200A Spark Issue

Postby monstermatt » Tue Jan 03, 2012 11:44 pm

Thanks for the info. I was just looking up how I could test them.




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