Topic: Blown Fuse - CB550k

[phrige]

I havn't had the bike started or anything for about 2 months now, while I was working on some other parts. getting tires on. Deciding what to do with the wheels etc.

Well I go to start it, no lights no anything. thats odd.
Check the fuse, 15amp-er is blown. Swap it out with a spare.
Blows right away. and its pretty hot at that.

Now i have a new fuse box with blade style fuses. I havn't touched any wiring. and unless somehow I chopped into some wiring while swapping out the front sprocket i think i may know a potential source.


 Since the bike was sitting for a while and the charge went down to a 9.95. I decided to charge the battery. That I did. now its at a nice 12.75, or 12.95 I forget. But when I was attaching the battery back into the bike. I accidentally shorted it, twice, to the frame.
Dumb mistake but I was doing it in the dark and was hoping to start it up that night.

Could I have fried something through the frame? Meaning something that was grounded to the frame getting blasted with a fresh battery charge when I shorted and got sparkage?

 Hoping not a rectifier or regulator....... any ideas?

[TwoTired]

I'd measure the rectifier.

If it even thinks about polarity reversal at 50-500 amps...poof.

[Deltarider]

I accidentally shorted it, twice, to the frame.

When removing the battery, undo the negative cable first.
When installing the battery fasten the positive cable first.

[phrige]

dang, so your sayin it is possible to fry the rectifier from accidentally shorting the battery to the frame?

Delta, The problem was one of my batter screws is a bolt, the positive i think it was wire kept falling between the battery and the battery box, and  once the pliers tapped the frame while spinning the bolt.

also just to verify, If I have a standard digital meter (not sure yet if it has diode Testing capability) is there any other good way to test the rectifier when its unplugged.  The fuse just blows the moment i turn the key so I'm not able to test it while its attached and presumably functioning.

[TwoTired]

With the rectifier unplugged, measure the ohms between the red and green.  If it is shorted you found the problem.  If you want to verify the diodes can still work, you need to diode check all six of them.

[phrige]

Thanks Two Tired. I'll check that later tonight.

[phrige]

So I tested the Rectifier,  Red/White to the Green in Ohm mode it read '3.04M'
 i'm unsure what a proper reading should have been.

[TwoTired]

Sigh.
Did you use the diode test function?
What does the meter's manual say about how to read the display?
Did you use both probe polarities?

[phrige]

When I reversed the leads I got O/L (overload). Which I believe is normal. (Normal in that, one way is overload the other way gets a reading.)

 I went and checked it in diode test mode. And it seems to have checked out OK, I tried testing all bottom 3 blades. Once while staying on Red/White and once through each with a lead on green. It beeped and read .500 each time.

I suppose the cause is something more sinister.

I tested to see if it was my flicking the lights on and off and turn signals which overloaded the circuit.    but no, the moment the key is turned from the off position to Position I (on). The fuse pops.


I gatta look up and see what possible symptoms may cause this kind of reaction.. Some Powered wire touching a ground? or corrosion between a positive and something else.?

[TwoTired]

I gatta look up and see what possible symptoms may cause this kind of reaction.. Some Powered wire touching a ground?

Probably.
You can connect a small lamp in place of the fuse.  It should glow bright, when you turn the key on.  Then keep disconnecting things until it suddenly goes dimmer.  When it does, you found the branch that is the problem.

Cheers,

[phrige]

Ooh! thats a good idea. Thanks man!

btw, it wont get to hot or anything right? Will 100watt bulb suffice. I don't want to damage any of the electrical by allowing too much power past. Hope the light knocks down as much of the wattage as possible. Not sure of the correlation between wattage and amperage.

either way I'll only have it on for short bursts. not on for hours straight.