Honda CB650 brake light problems

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Honda CB650 brake light problems

#1 Unread post by graymojocat » Fri Aug 08, 2008 10:02 pm

First, I am new to the biking thing. The bike we got is old and sat for a while and just needed a little TLC. I'm less than pleased with the shop we took it to. We told them it was sitting for a while and needed some love and a tune up. They didn't test the battery at all (which benefitted us because it's cheaper for us to replace it than let them do it), but we discovered the brake lights don't work either. (:sarcasm: great tune up guys. We bring you a bike that we tell you needs some love and a tune up and you don't even bother to test the battery or the lights. i'm impressed).
anyway. husband tested the voltage and it seems that it's not quite right. or as he put it "it's all over the place." Sorry I can't give you more.

But, since we know it's more than just the light bulbs, can anyone recommend what exactly he should check for fixing the problem?

He's all ready to go and just start working on it, but I really would prefer to have an idea or a plan of attack suggested by someone who knows about these things.

He is really handy and I don't think he'll mess up the bike or anything. His first car was one that he built.

Thanks for the help

Also, can someone suggest a good maintenance/repair manual? I know there are a bunch out there, but I don't want to randomly just pick one up and hope it's good.
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#2 Unread post by mgdavis » Fri Aug 08, 2008 11:59 pm

It sounds like it might be a bad ground? That can cause some interesting electrical symptoms. Were it me, I'd unplug and clean all the connections, hopefully that cures the problem.

IIRC, I had a Clymer's for my CB750. It seemed a decent shop manual.
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#3 Unread post by Sev » Sat Aug 09, 2008 4:30 pm

Basically you've just got to trace the circuits and see where the failure is. Do the lights "not work with front and rear brake"? Or does one brake switch work and the others not?

If just one works then you've got a problem with the other switch, otherwise it's the wiring leading from the switches up to the lights, or from the lights to ground.

Your running lights and brake light should share a common ground which means it's much more likely that you've got a flaw in the wiring along the brake light side of things. Should be a simple enough matter to trace back the wiring with a multimeter and test light to determine if there's a problem or not.
Of course I'm generalizing from a single example here, but everyone does that. At least I do.


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#4 Unread post by mydlyfkryzis » Sun Aug 10, 2008 4:17 pm

Before you do too much testing, remove the battery wires from the terminals. Clean the battery terminals and wire terminals and screws and bolts. Replace them and coat with weither a battery terminal protectant, white grease, or petroleum jelly. Any of them will work.

If you don't have one, get a battery tender (not just a trickle charger). The Deltran one is good (Battery Tender Brand) or get an equivalent.

Make sure the battery is filled, use distilled water.

Charge the battery completely.

Weak batteries and faulty connections will have you chasing problems than may not exist. Start at the beginning of the circuit (the battery), and work your way forward.

Good luck, I am sure you can get the bike fixed.
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