Header fuse blows....

[feelergaugephil]

1981 GS1000G

I put an inline wire/switch to turn the headlight off/on manually, it has worked perfectly so I don't think this is the problem.

With the headlights ON, after about 20 mins of riding the header fuse will blow, resulting in no headlight, dashlights, horn, turn signals or rear lights.
I am using a 10amp fuse (of which this is correct)

With the headlight off, No problems.............
I did an ohmeter check, with lights OFF...... 14.1----6 volts
""""""""""""""""""""""""""""""", with lights ON.......13.2----5 volts
I have a new Reg/rectifer, new battery and new starter celanoid.
Since the restoration I have only put on about 600 miles..
Any ideas why the header fuse blows?????

[Tom MLC]

Check the wiring in the headlight bucket. On my '78 1000 I had four wires that needed to be repaired. Insulation was cracked and brittle from overheating.

[anikmankar]

start the bike - all light on with headlights.

Check for hot / warm wires
Check charging with increased RPM
Check temp at rectifier

[argonsagas]

Did you, perhaps, opt for a higher wattage bulb that now may be overloading the circuit?

[feelergaugephil]

I bought a 55/100 headlight and then decided not to put it in, but I will check the other ideas this week...

[JayH]

55/60 headlight bulb was what came on your bike. A higher wattage bulb could cause enough of a drain on the charging system to heat up the wires and blow the fuse.

Be sure to check the conditon of the fusebox and wires for corrosion.

[argonsagas]

If you have not yet put in the higher wattage lamp, I would check out JayH's idea.

The contacts inside the fuse box are accessible by removing the cover panel at the back of the fuse box.

These contacts can get SO dirty that an overload not only occurs and blows fuses, ( due to the increased resistance) it can come into play ahead of the fuses, and cause the box to melt.

Been there, done that....replaced the box.