Is this a stock fuse tray?

[Guest]

Can anyone tell me if this is a stock fuse tray off a 81 GS 750L? I I just finished my motor rebuild and while attempting to get it running I heard a spark and now I'm blowing fuse #2 (from the top of photo 1) There is a replacement in the photo that's why it appears shorter. I've got a wiring diagram but I'm not sure if it is correct to the fuse box as it looks modified. The PO did a number on this bike.






Thanks a lot.

[Steve]

I don't have much experience with a 750L, but it certainly looks like a stock box.

If you are blowing #2 (counting from the engine), that is the SIGNALS fuse.
It powers the turn signals (obviously), horn, brake light and warning lights (low oil, neutral).

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[Weeksz]

Thanks Steve. Any guesses why I've started blowing this fuse? I was attempting to jump start my bike. I know.. I let me eagerness get the best of me.

[78550GS]

Thanks Steve. Any guesses why I've started blowing this fuse? I was attempting to jump start my bike. I know.. I let me eagerness get the best of me.

Was the other vehicle running? This may be the cause of your issue.

[Steve]

Not sure why jump-starting the bike would blow a SIGNAL fuse, but it's a fact that you DON'T want the 'donor' vehicle to be running during the jump start.

I was going to ask if this appeared suddenly or if you did some work just before this happened, then I re-read your first post. You just did a "motor rebuild". Go back, check EVERY connector that you pulled apart and, hopefully, put back together correctly.

Look around the motor mount to make sure you didn't pinch a wire behind a washer. Just look all around SLOWLY, examining everything, you will probably find it by looking, no testing (and blowing more fuses) necessary.

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[78550GS]

Not sure why jump-starting the bike would blow a SIGNAL fuse, but it's a fact that you DON'T want the 'donor' vehicle to be running during the jump start.

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The point I was trying to make. Thank you.

[Weeksz]

Yes. I just completed a top end rebuild on the bike. The battery was dead and i was attempting to jump the bike with the donor vehicle off, It would crank over and was not blowing fuses..It would crank but it didn't seem like it was getting enough volts so I decided to put the battery on the charger. When I returned to the bike after letting the battery charge the indicator on the charger showed that the battery was not taking any charge at all and is when I realized that the battery was toast. So my dummy self decided to put the charger on 40 amp and try and turn it over. Well I Hit the starter once. Didn't not like how it sounded and immediately unconnected. Discovered that a fuse blew. After replacing the fuse it continued to blow after re connecting it to the non started donor car again, as soon as I put the positive cable to the battery. I have a feeling that something is fried I'm just not sure what. The wire harness on this bike is old and full of soot (wires are dark and dirty) and there are splices and things all over it. Its a real mess. I had planned to rework the wire harness when I got the bike running but it looks like this will be first. What would be the first thing to go if it was overpowered?

[Steve]

Putting the charger on the 40-amp setting was your mistake.

If, by chance, it was also putting out about 15 volts (which is not uncommon for chargers), your R/R (voltage regulator) would try to regulate that down to 14.4, or so, and would fry itself in the process, as it's rated for about 25-30 amps. THAT is why you don't want your donor vehicle to be running. Since virtually all 4-wheeled vehicles on the road today have variable-field alternators, they can easily exceed the capacity of the R/R while idling, let alone running at a fast idle.

What would be first to go? Probably the R/R, but that would not blow the SIGNAL fuse. (Well, let's just say that on my 850s, 650 and 1000, that is the SIGNAL fuse.) If the R/R were to short out, it would take the MAIN fuse, which is the fourth fuse.

Next item to go, due to over-voltage, would probably be the ignitor, but that is on the third fuse, and over-voltage does not blow a fuse, it's over-current.

As mentined earlier, the second fuse (assuming that it is the SIGNALS) powers the horn, turn signals, brake light and instrument panel warning lights, so look for a pinched wire in the horn harness, oil pressure sending unit or brake light harness, as they are all right next to the engine, and might have gotten pinched when things got put back together.

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[Weeksz]

Hm you know what. Now that I remember correctly the first fuse to burn out was the fourth fuse. I'm sorry. after I replaced that fuse I moved some things around before I returned. After I replaced that fourth fuse the signal fuse was burning out afterwords, two or three times after I checked other connections and trying to troubleshoot.. So that being said, is it possible that since the R/R is fried then it is sending to much voltage and blowing that signal fuse?

[Steve]

..., is it possible that since the R/R is fried then it is sending to much voltage and blowing that signal fuse?

If the R/R is fried, it will likely blow the fuse as soon as you turn the key ON, and not wait until the engine is running.

Remember, it's not over-voltage that blows the fuse, it's over-current.

And, ... the fourth fuse is the MAIN fuse, which is the one that would blow if the R/R is shorted.

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[Redman]

Blowing signal fuse ....
I always suspect a faulty horn.

And, no, do not have to press the horn button for a faulty horn to blow a fuse. Is power to horn al the time, the horn button connects the negative.

Try disconnect the horn(s) and see if doesn't blow the signal fuse any more.

Traverse City, eh?
Wife and I are from Traverse City.
Well, wife more so than I, several generations, 1800s, light house operators.
I am more of a tourist compared to that.

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[Weeksz]

If the R/R is fried, it will likely blow the fuse as soon as you turn the key ON, and not wait until the engine is running.

Remember, it's not over-voltage that blows the fuse, it's over-current.

And, ... the fourth fuse is the MAIN fuse, which is the one that would blow if the R/R is shorted.

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Steve-

Yes, it was blowing the signal fuse as soon as I turned the ignition on - is this what you mean or are you talking about the Main fuse (#4) burning when the ignition is turned on? It only burned the Main fuse the initial time I jumped it.