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Electric just conked out on 78 CB750F

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Rockwork

Electric just conked out on 78 CB750F

Where do I start to diagnose a complete power outage?

Since replacing the ignition a month ago, I've had no electric problems. After a long ride home tonight, I was backing into the curb, and when I bounced it kind of hard everything went off. No oil, neutral, or front lights.

Thank you for any clues.

"To strive, to seek, to find, and not to yield."

shultz_1978

Re: Electric just conked out on 78 CB750F

Try the main fuse.

Its a start

Simple if some one else can, why can't I
Jamie

shinyribs

Re: Electric just conked out on 78 CB750F

Administrator

Shultz is right. The main fuse blowing is very common on these bikes. If you bypass the factory fuse box and install an inline fuse holder it will pretty much cure the problem forever. I run a 30 amp fuse in my bike.

Rockwork

Re: Electric just conked out on 78 CB750F

In reply to this post by shultz_1978

Thank you. Great suggestion, but didn't fix the problem. Pulled the main fuse, which looked intact, and replaced it with a spare, but still an electric blackout. What's the next thing to check?

"To strive, to seek, to find, and not to yield."

shinyribs

Re: Electric just conked out on 78 CB750F

Administrator

Do you have a volt meter? The best thing to do will be to just start at the top: Check for voltage at the battery then work your way down. Battery, other end of the battery cable, battery side of the start solenoid...etc. It is possible that the bump damaged the battery. Rare,but possible. It may have knocked loose and shorted out a plate or two.

Rockwork

Re: Electric just conked out on 78 CB750F

OK, must not be the battery since I just jumped it from a car and still no sign of life. Seems like I need to get a voltage meter and start probing as you suggest.

Thank you for continued input.

"To strive, to seek, to find, and not to yield."

TOOLS1

Re: Electric just conked out on 78 CB750F

Administrator

Check the wires on the back of the fuse box. The soldered connections there are notorious for going bad. I always replace my fuse boxes with the spade type wire in fuse holders. Then I use a spade type 30 amp breaker for the main.
TOOLS

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1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
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Rockwork

Re: Electric just conked out on 78 CB750F

Guys, thanks a bunch. It was the main fuse. But the order of the fuses is different than it appears in the manual, so I didn't notice until closer inspection today.

I'll arrange to change the fuse holder. Can you give me a link to what you recommend?

Thanks again.

"To strive, to seek, to find, and not to yield."

shultz_1978

Re: Electric just conked out on 78 CB750F

Glad you go it sorted out. Yep on the road again

Simple if some one else can, why can't I
Jamie