Lost electrical power - Page 2

Axeman88 · 06-09-2024, 12:41 PM

Reviving an old thread to share what I can regarding blowing the 20A main fuse while cruising.

I experienced this happening 4 times on a recent LONG ride (370 miles each way). The fuse blew once at about 320 miles on the way out, then 3 more times on the return journey. I had previously ridden this machine for short trips locally about 1500 miles over the last year without ever experiencing the issue. Also, pertinent to one suggestion, I monitored charging voltage on the bike previously, while riding and idling, and it was consistently below 14.2 volts at all times. I will check charging voltage again, soon to make sure this hasn't changed.

My suspicion is that this is most likely a vibration related issue, (or perhaps heat) and is likely due to insulation on the RED wire that goes from the Main fuse to the ignition switch, being compromised at some point, and that wire shorting to ground at that damaged point. Because I had heavily loaded the plastic tool tray under the seat for my trip, this area is my initial suspect.

I'll report back if I get more info on what caused the main fuse to blow 4 times in 700 miles.

Vegas Street Rider · 06-09-2024, 06:23 PM

Look forward to hearing what you found regarding your issue. It does sound like an exposed wire shorting to ground. Hope the hunt is short.

Axeman88 · Today, 02:21 AM

As could be predicted, my issue with blowing main fuses didn't fix itself, and progressed to the point where I couldn't ignore it any longer. Once I pulled off the Seat, Right Side Cover, and Fuel Tank, diagnosis and repair went quickly. It was, as I had anticipated, a fault in the insulation of the RED wire that goes from the Main Fuse to the Ignition Switch. This wire is live all the time since it's part of the main power circuit and in front of the ignition switch. Vibration had worn through the tape wrap around the harness and through the insulation at a point where the wire harness runs through the top engine mount. It was easily found and easily fixed. To repair, I used a little liquid electrical tape, then over-wrapped with electrical tape, adding a bit of bicycle innertube for extra protection at the wear point.

For this kind of job, I like to use a "beeper", that I put in the circuit in place of the fuse. This leaves my hands and eyes free to manipulate the harness into likely positions. With the ignition switch OFF, when the short is made, the circuit is completed, and the beeper beeps. This is much more efficient than using a meter or even a test light, and certainly better than blowing a bunch of fuses trial and error fashion.

Finding the short took less than two minutes. Maybe I got lucky, but the position seemed obvious. It's hard to imagine a harsher location than over the hottest point of the engine, and at a point of maximum vibration transmission. My next suspect would have been at the Ignition Switch. The wire bundle entering the Headlamp Housing, also looked like it could be better protected. Oh well, if it ain't broke, ......

Vegas Street Rider · Today, 02:33 AM

Glad you found it and that it was an easy fix Axeman88. I had the same issue except mine was in the headlamp housing where the wire went into the multi terminal. I ended up cutting it at both the incoming and outgoing point and just direct wiring it. Problem solved.

Thanks for the pics as well. Safe riding.

06-09-2024, 12:41 PM	#11
Axeman88 Junior Member Join Date: Jun 2024 Posts: 23	Main fuse blows while riding Reviving an old thread to share what I can regarding blowing the 20A main fuse while cruising. I experienced this happening 4 times on a recent LONG ride (370 miles each way). The fuse blew once at about 320 miles on the way out, then 3 more times on the return journey. I had previously ridden this machine for short trips locally about 1500 miles over the last year without ever experiencing the issue. Also, pertinent to one suggestion, I monitored charging voltage on the bike previously, while riding and idling, and it was consistently below 14.2 volts at all times. I will check charging voltage again, soon to make sure this hasn't changed. My suspicion is that this is most likely a vibration related issue, (or perhaps heat) and is likely due to insulation on the RED wire that goes from the Main fuse to the ignition switch, being compromised at some point, and that wire shorting to ground at that damaged point. Because I had heavily loaded the plastic tool tray under the seat for my trip, this area is my initial suspect. I'll report back if I get more info on what caused the main fuse to blow 4 times in 700 miles. Login or Register to Remove Ads
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06-09-2024, 06:23 PM	#12
Vegas Street Rider Senior Member Join Date: May 2015 Location: Henderson, NV Posts: 1,108	Look forward to hearing what you found regarding your issue. It does sound like an exposed wire shorting to ground. Hope the hunt is short.
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Today, 02:33 AM	#14
Vegas Street Rider Senior Member Join Date: May 2015 Location: Henderson, NV Posts: 1,108	Glad you found it and that it was an easy fix Axeman88. I had the same issue except mine was in the headlamp housing where the wire went into the multi terminal. I ended up cutting it at both the incoming and outgoing point and just direct wiring it. Problem solved. Thanks for the pics as well. Safe riding.
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