Topic: Another Problem

[Thfireman]

I have been trying to get my Wife's CB750F Super Sport road ready.  Finally got it running pretty darn good.  But the other day I went to start it and notice that all the lights were out and the starter wouldn't operate.  I checked the fuse box and the 15 amp fuse (Main) was blown.  I also observed that the left side of the fuse clip had melted the plastic around the clip.  However someone had put a 10 amp fuse in the spot instead of 15 amp.  I removed the fuse box and looked in the back where the wires were soldered in.  I could see no problems other than the melted plastic.  No crossover to the fuse above and no loose wires or clips.  Anyway I replaced it with a 15 amp.  When I turned the key on the neutral light, headlight and others worked normally.  I waited a minute then started the bike up with no problem.  All was good I thought, no blown fuse....GREAT!!  Wrong   Before I replaced the side cover and while the key was on I touche the new fuse and Whammo!!  I got burned.  Hot as hell...Whats up with that.  But the fuse wasn't blown.  I don't understand.  Obviously there is a short somewhere but why is it so hot but the fuse isn't blown.  I turned the key off, it cooled down.  I turn it on and it heats up, sometimes hotter than other time but still heats up.  The wires get warm but not hot.  It appears to be the red wire from the fuse to the key switch according to the wiring diagram.

Any Ideas?  How do I trace this problem.  I need help.  Thanks!

[kslrr]

Sometimes dirty connectors in the headlight bucket, where all the cicuits come together, can cause over current issues or insulation on a wire is rubbing through and grounding on the frame.

[beelsamin]

Try removing the fuse,clean the metal contact,then clean the metal on the fuse seat,the seats and fuse are corroded and creating resistance which equals heat. I had the same problem with my 78 cb550 and thanks to the forums here I took their advice and my fuses no longer get hot.

[cadaver]

i have about the same issue and at this very point in time have my wire harness and electric box in my lap and cleaning all connectors and then when that's done unwrap the front of the harness first and see if any wires are touching ..good luck with yours ..if i find anything ill let you know what i find and then maybe that will give you some help

[Thfireman]

Hey ,  thats all very good information and great tips.  I will start with cleaning the fuse older and terminals and checking the headlight bucket just as soon as this rain stops.  Thanks again.  Anyone else with other ideas please let me have it. 

Roger

[kghost]

Corrosion=Resistance=Heat

[Bido]

I can't say enough about cleaning the connectors. I had all kinds of charging problems and spent time and money on parts I didn't need until I took the time to clean all the connectors I could. I also found a rusted socket on my rear right blinker I think the water gets in when the bike is on the kickstand I plugged it up with some putty. I made a tool to clean the square connectors with a nail file I ground to the size of the male side of the connector. After cleaning, spraying with contact cleaner and applying Dilectic grease to all connectors the bike charged like it was new. It took some time but it was well worth it.

Good luck

Bido

[cadaver]

OK Thfireman...this is what i found when i took my harness and everything that disconnected off of the bike ..NOT A DARN THING!!!...but what it may have been, like others have said is you half to clean all connections..... I mean All..even the fuse box ... I use a dremel and i nice little bit to clean and some electrical grease that makes for a better contact .  hope that helps you at all ..don't be afraid of the headlight wire Assembly ..all you need is a good wire diagram ..looking for that should be the first thing that i think that you should do and then the rest kinda falls into place and the help of the good people around this place..good luck

[Thfireman]

That sounds like a plan everyone.  I will start at one end and work to the other.  Thanks all!

[Thfireman]

Well I buffed and cleaned the fuse clips that hold the fuses in.  I also cleaned and polished the plug for the fuse box harness, then added elrolitic grease.  At this point I switched on the bike and no heat build up.  I cranked it and no heat build up.  I wiggled, jiggled and pulled on wires and still no heat.  I will stop at this point and ride the bike for a while and keep an eye on it.  This winter I will pull all connections and clean and grease them.

It must have been the resistance thing, so thanks all.  You all are the besteses!

Roger

[Hush]

Problem solved then, and something for all of us to remember.

[cadaver]

nice ...I'm glad that your problem is no longer ...and i haven't popped any fuses myself ..now i just gotta tackle my charging system ..

[Thfireman]

Yup,  seems to be fixed.  My Wife and I went for a long ride tonight.  I followed her around on my 900 custom.  No problems, no hot wires.  Whew,  Now we can relax and ride before it gets cold.   Thanks again all!

Roger