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Electrical Woes 86 Interstate

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I rode my 86 from Texas to Michigan, the bike performed beautifully, starting on the first turn in 34 degrees.  I started the bike several times since arriving 2 wks ago then a few days ago refused to start, has weak spark and backfires when I release.the start button.


Then yesterday while trying to fix the issue the starter solenoid refused to engage, it's gone dead.  it was too dark to continue so today will start by rechecking fuses, and searching for the obvious things like loose connections.


My question, why the weak spark issue?  Digital volt meter shows 13.4v. key off.  12.5v key on, sustained voltage during crank. 11.5v. battery is new gel deep cycle 300 cranking amps, and I have a 400 amp boost box, the issue isn't low voltage, I have a loose wire or faulty connection, can anyone help explain what will cause weak spark.  I'm not novice in repair I need help in theory.  many thanks to all

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Jim, I would start off by checking the solenoid connector. If you haven't done anything with it like bypassing the 30a dogbone fuse, the chances are right there is most of your problem as that connector both has the fuse and connects the starter button/ground to the relay so it can energize and start the engine. Over time the dogbone connections will get hot and burn and that might have toasted the starter connections...


Let me know what you find....

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thank you for your response.  The solenoid is of the finest china has to offer.  All fuses are good and fusing, the solenoid is sticking, I use a screwdriver to short the terminals.  





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First Thank You Support with help logging in. 

I got the bike to fire, it popped and showed signs of life.  Today is rain.

What was the final fix you ask?  So do I.  I replaced worn out elec. tape with non adhesive tape/shrink/stretch wrap.

I separated all connections sprayed with WD-40 and reconnected.

I had one oh wow moment when the voltage regulator case sparked.  The three yellow wires feeding it had tears in the insulation very close to the regulator body, causing the sparking.  I taped and wrapped each yellow then ran a voltage test on the case for integrity. Today I will encapsulate the harness/regulator connection in silicone making sure the base of each yellow is isolated.

I removed all 4 connectors from the coils plugged them back in insured secure.  

it was a wonderful feeling when it popped.  

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