Topic: My crazy ass fuse box!

[Ryan 550k]

The craziest thing just happened to me tonight.  I'm on my way home, heading over one of the ten thousand bridges we have here in Portland, OR, and the power on my 550 started going in and out....then just out.  So I pull over, check the fuse box and as I jiggle one of my fuses, second in from the right, it's really hot, it starts to spark and my lights start to flicker, THEN the little piece that holds the fuse in place literally pulls right out because the plastic it was embedded in has melted!  What the #$%*?!  So there I am on the side of the bridge holding the fuse in one hand and the piece that's supposed to be connected to the fuse box in the other thinking, well what the hell do I do now???  I always carry fuses on me so I replaced it, then decided to jam the piece that holds the fuse back into the fuse box where it was and suprisingly it worked....and stayed.  Although I don't trust it to stay for long, it did get me home though.

So the question is, why the heck did that fuse get so hot?  Do I have a bad wire somewhere?  Obviously I need a new fuse box, I'll work on that over the weekend.
Anyway, ya.  I'd love to hear some thoughts.

[narcoticrex]

are your fuses rated too high?  like using 20a fuses or something, allowing more current to go through and melt something?  unlikely but you never know.  or perhaps the fuse was acting almost like a resistor, allowing some of the electricity to go through, but not all, and what was left turned into heat and voila...maybe your system is being overcharged and caused that.

but hell, i learned everything i know from reading these forums for a couple weeks and a haynes manual so dont take my advice! 

[merc2dogs]

a loose connection either the clip at the fuse itself, or the wire to the clip.
An overdraw would blow the fuse itself, while a bad connection will warm it up as you noticed
Ken

 
   

[mark]

These bikes have fuse box issues.

I'm not using mine anymore.

http://forums.sohc4.net/index.php?topic=20035.0


Happy trails.

[TwoTired]

I've seen the aftermath of just such a scenario.

One -  the fuses naturally get warm when carrying current.  When they carry amps above their fuse rating, they heat enough to melt.

Two- The fuse to clip contact can become resistive (an oxidation layer).  Pushing current through resistance creates heat.  This heat is added to the fuse generated heat.  The heat is dissipated by the area of metal of the fuse clip and, the fuse end cap, which is a pretty small area.  Heat also gets conducted to the wires soldered to the fuse clips.  But, they have an insulated coating that impedes heat dissipation.

Three - The wires soldered to the fuse clips can become  "less soldered" from fuse and clip heating.  The reduced contact area can also generate heat, forcing larger currents through too small a cross sectional area.

And speculation:
I suspect you may be using a higher than specified fuse rating to overcome fuse melting issues, rather than polishing the fuse clips for low contact resistance.
You may not have told us about bigger/brighter headlight installations or other electrical mods that would draw more current through the fuse, fuse clips, and soldered wire attachment.

That's enough thought for now...  See also:

http://forums.sohc4.net/index.php?topic=2206.msg15923#msg15923

Cheers,

[bistromath]

Had the same thing happen to me on my 550F, using stock-value fuses. Also used to blow fuses occasionally. Polished the contacts of my fuse box THOROUGHLY (using 320 sandpaper and finishing with an acetone wipe) and bent the contacts closer for increased spring force, and it hasn't happened since.

[Ryan 550k]

Hey Mark that's a great idea!  I'm gonna work towards that.
Thanks everyone.  This site is the greatest.

[eurban]

It is difficult to find the correct size fuses for the stock fuse block and often time people install the wrong length fuse into the clips.  This gives a smaller point of contact with the clips and can add to the heat build up.

[fixahonda]

Mine 550 used to do the same thing to me before I cleaned up the contacts in the box. In fact the box that came with the bike was kinda melty when I got it.

The worst and final case of this behavior was at 6pm on the side of a busy highway. Bike dies, I coast to the side of the road whilst cursing not quite under my breath. Of course I have no extra fuses with me so now what?
I am sitting on the side of the road contemplating my situation when I spy an empty cig pack on the ground. Inspiration struck. I tore some foil from the box and wrapped it around my blown fuse. Made it home no problem. Cleaned all of the contacts and replaced the fuses the next day.

[76 cb550]

My fuse box was burned out when I got the bike.  One of the terminals was completely gone (direct wired...poorly) the wire that went to that terminal was in TERRIBLE shape...completely burned up.  I got a new (used) fuse box and rewired it.  The contacts on it were pretty loose and shoddy so I eventually just put inline glass fuses in.  Blade fuses were recommended but I chose glass can't say why really.

I recommend just installing inline fuses and labeling them.  Easier but not stock.


(PS not an expert by any stretch of the imagination)

[cb350twin]

Had the same thing happen to me on my 550F, using stock-value fuses. Also used to blow fuses occasionally. Polished the contacts of my fuse box THOROUGHLY (using 320 sandpaper and finishing with an acetone wipe) and bent the contacts closer for increased spring force, and it hasn't happened since.

Agreed

[Ryan 550k]

Alright, lots of great stuff here.  Bare with me for a sec though, I'm a newbie.  When you guys say contacts are you talking about the pieces that hold the fuses in place?

[mystic_1]

Yup, the little metal clips that hold the metal ends of the fuses.  You want the inner faces that actually touch the fuse to be as clean as possible.

mystic_1