Topic: Electrical problem/fuse blowing...

[jdpas29]

okay, let me start off by saying that this bikes electrical situation is somewhat rigged.  although after i looked at it intensively last summer and winter, it did have most everything in the right spot and original wires were there.  some were burned and i replaced/patched them.

i don't have a voltmeter so i can't give you guys a whole lot of info other than the symptoms, but here goes.

the fuse box has only two fuses in it a 15 amp main connected to the two big red leads - looks right.  and a 7 amp for the tail light connected to two brown wires - looks right.  there is another fuse that looks like it was originally meant to take the place of the headlight fuse.. it was made inline and is a 7 amp fuse.   this one i'm concerned with. 

i have power to the bike.  the bike runs great.  the battery charges and holds a charge.  but i blow fuses and fuses get very hot on the right side of the fuse holder facing the wiring on the side of hte bike... so i guess toward the rear if that helps.  it doesn't seem to stay hot though.  it has waves of heat that go through the fuse with or without doing anything.  this made me think short, but i wanted to get another opinion.

the headlight works too!  which i though was strange considering that the little inline fuse seemed to have no effect on whether the headlight worked or not.  tell me,  will your headlight work if you remove the headlight fuse???  from my experience in wiring i though this was not right unless the fuse was just for the left hand switch on the handlebars.  my first guess... and tell me if this is plausible....  is that the wrapped wires going from the body of the bike and the posterior wiring area to the headlight are scorched/melted and the Br/R wire that is supposed to be the headlight wire is touching another hot from some other part of the wiring.  this way the headlight is working with or without the headlight fuse AND it's overheating the main 15A fuse.  does this make sense? 

i know this is very confusing, but any help is appreciated. 

Jeff

[TwoTired]

It's particularly confusing, as you don't state the model of your bike.  Gotta be 10 or more different wire diagrams for the SOHC4.  Is your bike currently wired close to any of them?

If your fuse holder and fuse is getting hot, you are either very close to the fuse's current limit capability, or the clip contacts are oxidixed, resistive, and contributing heat, or both.  There could also be connections on the back of the fuse block that are resistively heating.  And, metal conducts heat.

Cheers,

[jdpas29]

ahhh... durr..  thanks for responding two tired.  why do i always forget the most pertinent information?  the bike is a 750K8.

i got out there tinkering though and i think i figured it out.  i got the fuse to cool down anyway.  see when i originally rigged the bike, the only way i could get everthing to work lighting-wise was to run the bike in the P (park) position.  i know that sounds dumb but it was all i could do.      i just figured out how to make everything work in the ON position like it's supposed to.  also... i think most of the heat was coming from a dumb error i made back in the summer when i took off the turn signal buzzer.  i just stuck the Br/b leads together in a loop.  they were just making a loop and overheating the fuse i think.  anywho....  i'm going to go get a new headlight and take her for a spin.  i'll get back with you if it continues to blow fuses.  i have my fingers crossed though. 

thank God for good wiring diagrams!

 

just as a trivia question...  do halogen bulbs put more or less strain on a fuse with regard to amps?

[TwoTired]

The watt rating tells the story.  Stock headlight was 40 W low beam 50W high beam.  If your halogen has a higher watt rating, it draws more current.  Divide the watts by 12 V to get the amperage draw. Example 40 Watts would be 3.33333333333333 Amps, according to my calculator.

Cheers,

[oldbiker]

Gosh TT and I thought it was 3 1/3