Topic: Blowin Fuses?????

[hiljak]

I seem to have an electrical issue going on....here's the skinny:
1971 CB750
stock motor
no turn signals
no guages
no front brake
headlight and tail/brake light only

the issue is I am blowing main fuses. It seems to occur inconsistently when I step on the brake pedal. I can ride for 20+ miles on the highway and when I get into stop n go traffic in town I can stop at several red lights then without any indication the fuse will blow. I think it originally called for a 15A fuse and I've been blowing 25A fuses.

All removed electrics were simply unplugged and the ends are secured and dry and not touching anything. I also replaced the brake switch and have double/triple checked all connections.....WTF?

[CB750Ken8]

Does it happen to blow more when you use your turn signals and stop or just sopping? if it blows when you use turn signals there's your answer.

[kvallelunga]

Stock fuse holders? If so take a small round dowel about the size of the fuse in diameter and wrap it once with 220 grit paper and clean the contacts until very shiny. The fuses are getting hot from the resistance of the conductors to fuse body contact. Common problem

[Bodi]

Look for a wire rubbing against the frame or fender, the rear brake switch wire and the brake light wire under the seat are the obvious suspects. Something may be worn inside the harness too but that's less likely and you would maybe see the outer sheath worn through. The brake light circuit goes through the whole harness from front to back since there's a front brake switch. This connects inside the headlight shell I think, a common spot for wiring to come to grief.

[worlddrum13]

i had the EXACT same thing happen with my 750. i ended up taking apart and cleaning EVERY connection for my lights. it was inconsistant, like you said, so it was hard to figure out what the actuall issue was, but i did this a year ago and it hassnt blown a fuse yet

[hiljak]

Thanks for the suggestions...I'll try the fuse block trick first. I've already tried to trace the worn wire scenario...

I appreciate your help.

[Nikkisixx]

I seem to have an electrical issue going on....here's the skinny:
1971 CB750
stock motor
no turn signals
no guages
no front brake
headlight and tail/brake light only

Is it the turn signal     Sorry ken, couldn't resist.
 Anyways, sounds like you're on a custom or bobber or chopper. Do you have a custom tail light with a big ass bulb drawing too much amperage?

[hiljak]

 Anyways, sounds like you're on a custom or bobber or chopper. Do you have a custom tail light with a big ass bulb drawing too much amperage?
[/quote]

Not really a "custom"....just a stripped down CB. Tail light is aftermarket but uses a simple 1157 bulb....

The brake light works fine for a while but on a recent 25 mile city ride, it blew fuses 3 different times.....I probably hit the brake 100+ times without any problem?

I'll try a few of these suggestions over the weekend....

[CB750Ken8]

I seem to have an electrical issue going on....here's the skinny:
1971 CB750
stock motor
no turn signals
no guages
no front brake
headlight and tail/brake light only

Is it the turn signal     Sorry ken, couldn't resist.
 Anyways, sounds like you're on a custom or bobber or chopper. Do you have a custom tail light with a big ass bulb drawing too much amperage?

Well I figured he meant he had no turn signals and everything else AFTER the fuse blew which would be logical.

[cb350twin]

Check and see if the metal prongs are getting hot in the fuse box and or if it's melted. If it is just get a new one through David sliver spares there cheap enough. I know its saved me a load of trouble! seems like cleaning them only works for so long and is still iffy after so I just went with new.

http://www.davidsilverspares.co.uk/CB750K5-FOUR-1975-USA/part_105956/