Topic: Running great then completely shut down, help please

[JP]

Hey guys,
I searched the electrical problems for a while but couldn't find anything like my prob, so here goes-

I just bought another 550 yesterday and man is it clean!  I'm very happy with it, it has been in storage for the last two years, so I swapped out the carbs, fresh fuel, new battery and VROOOM!- it fired right off.

I rode it to work this morning and got my first sign, it wouldn't go past 60mph, so I backed off and took it easy for a while.  Then it started running better and I figured it just needed a nice long warm-up after sitting so long, 60mph was no problem and I just brushed off the whole idea.

At lunch, I rode for about 3 miles and all is good, running great and then- nothing.

It just lost all electrical power with no hope of it comming back.  I coasted into AutoZone and checked all connections, fuses, ex.- no clue.  Lights won't work or anything.  I figured the only thing that can do that is the ignition, so I went in and got a jumper lead and tried jumping out the ignition switch- no good.  Checked the battery and it was strong.  Checked my grounds at the coils and down by the battery- both were fine.

Any clues?

[TwoTired]

Pretty common for the fuse clips to oxidixe and forms resistive layer. It can be transparent.  However, the resistance generates heat and melts th fuse near the end cap.  cleaning the fuse clips and replacing the fuse usually gets things going again.

Check out the thread;  "WTF Fusebox melted".

The 60 mph problem could be points related, with oxidation on those, too.

These bikes don't like to sit around, and are kind of #$%*y afterward.  They seem to enjoy a good flogging on a daily basis.

Check your tank for rust, and contamination of the fuel.  It only takes a small piece of crud to block up the 0.016 inch orifice in the slow jets.

Cheers,

[Gordon]

Yep, bad fuse clips should be first on the list, and then possibly corroded wire connections on the fuse block.  I know you already said you checked the following areas, but other than a short somewhere in the main harness, the only things I can think of are a bad connection at the battery or ground wire, and a loose clip on the ignition switch.  You should also check the rat's nest inside the headlight shell.

[JP]

Well that was quick!  I talked my boss into letting me go out and troubleshoot while back here at work and he came out with me.  So, we checked everything thoroughly- even up in the ends of the fuses and both of us came up with nothing.  I kept whining about a meter and he's like, "I got one."

Long story short- the rear-most fuse was blown!  I checked it 4 times with the meter to make sure, because I have it in my hand right now and still can't see the break!

Moved 'em around and Vroom!

What doe's that fuse go to anyway?  I suppose, the ignition?  I replaced it with the middle fuse, so what won't work now?

You hit the nail right on the head TT.
Thanks so much,
JP

[TwoTired]

 I believe there are two 7 Amp fuses headlight/ tail light, and one 15A main fuse that most everything electrical uses including the head and tail lighting.

Given your description, I'd guess your 15 A main went.   They are marked on the end caps.  A 7 Amp one in the main position will probably blow when the you turn on the headlight and run the bike.  Unless it's the headlight fuse you robbed.

Which year and model do you have?

If you have a 3 fuse block, the spare will be in the cover for the fuses.

The later models have 5 position fuse blocks and the spares were put in the outer positions.

Make the effort to get the correct 1 inch fuses.  The 1.25s will work in pinch, but don't make complete contact, which can also lead to heating.

Cheers,