Kawasaki KC100 Electrical gremlin... HELP!

[eunos20b]

Hi all,

Very new to bikes, this is my first and so far I love it. It's in a bit of a sorry state but piece by piece have been restoring it with many plans to come. Anyway long story short -

Bought bike 2 weeks ago. Lights worked at time. Booked bike in for MOT on Wednesday, one of the failures was 'brake lights not working'. Bloke says he couldn't get any lights on, regardless of what ignition location. Poo-poo'd it till I got home hoping for the best, but low and behold no lighting. Checked fuses coming from battery, positive fuse burnt out. Went and got new 10a fuse from Tesco and fitted. Now the negative fuse - whenever I turn on ignition - glows bright red. What am I looking at here? I'm totally clueless with electrics! Bike runs cushty apart from that!

Looking forward to documenting my resto on here for those interested.

[JRH]

Hi, welcome. Pop over to newbies and introduce yourself when you have time.

Fuses are not fitted in the negative lines.

Are you sure it is in the negative? If it is a fuse and is glowing red something is pulling far too much current, or the fuse is too small. Without a circuit diagram it is not easy to say what.

If you are going to do work on the bike it would be worth getting a Haynes manual, that would have a diagram which would throw more light on the problem.

Sorry can not be more help at the mo.

Edit

KC and KH seem to be similar bikes and have found a KH diagram. There is only 1 fuse and it is in the positive.

Have a look at this and see if you can identify the part that is glowing.

[ThePhatomfart]

Hi , it looks like you've got a short on the wiring somewhere on the loom, what i would suggest is unplugging the lights wiring connections so that no lights are connected, turn on the ignition and see if the fuse is glowing, if it isnt ,then reconnect lights one by one checking that the fuse isnt glowing ,When it does glow thats the problem circuit, that way you can narrow it down to a set of wires, I think it could be just lights wiring somewhere on the bike as you said they were working before,(this is just to check your Lights wiring system, can also be used to check all components one by one)

[Adam]

Could be a wrong bulb drawing too much power, so once you narrow it down take the bulb out and check if it's the correct one. I once put a xenon bulb in my WR, it worked fine however every time I stopped the bike would cut out. It was a 100W bulb, standard is 55W as soon as I swapped it back the problem was solved.

[eastanglianbiker]

if a fuse is glowing ed and not blowing then it is far to high rated and as said it sounds like you have a direct short somewhere keep playing with it and not finding the problem could result in a wiring melt down and fire

[eunos20b]

Thanks all, quick and informative replies.

There are fuses, one on each pos. and neg. wire, say 3 inches of wire from each batt. terminal. As you all say, I'm just going to have to go through the lot and narrow it down, it's going to be a long Saturday It's a good thing I love the bike!! Will report back later. Thanks again.

[Cablefix2000]

Does a kc100have a voltage regulator? I just purchased vintage kc100 with the wiring harness bastardized, it has running without a battery, im trying to make the lights to work, the voltage shoots up to about 50 volts ac when the engine is running no reading in dc scale from the headlight bezel area, can somebody please shoot me a copy of the electrical schematic so i can trouble shoot ifo not know where to start. The previous owner hotwire the bike ignition switch and i also neef to fix that..., please help with the wiring diagram

[Guest]

Thanks all, quick and informative replies.

There are fuses, one on each pos. and neg. wire, say 3 inches of wire from each batt. terminal. As you all say, I'm just going to have to go through the lot and narrow it down, it's going to be a long Saturday It's a good thing I love the bike!! Will report back later. Thanks again.

 

Think about this......as JRH says, there should be no fuse on the earth side of the electrical system. If there is, then somebody's been in there and bodged it up. What would be the purpose of such a fuse? There isn't one, so whoever put it in didn't know what they were doing. From what you say, it sounds like a short somewhere. Check the loom near the headstock and especially the bit that moves with the bars. When you say "the fuse is glowing", what do you mean? What sort of fuse is it? Is it a blade type? What is the rating? A photo would help. Are the lights working again now that you have replaced the fuse that was blown?

[exportmanuk]

Hi A fuse will glow if its about to overload they are basically a bit of metal that melts

You have some good suggestions I would probably start at the head stock try turning the bars full right then check for a minute or two then full left. On older biked the wires insulation ( plastic cover) becomes brittle and breaks allowing a short circuit. The head stock area has to flex every time you turn the bars to this is usually the first place they go.

Unfortunately its going to be trial and error to find it. May be worth considering a new loom or making one yourself

[Guest]

Hi A fuse will glow if its about to overload they are basically a bit of metal that melts

You have some good suggestions I would probably start at the head stock try turning the bars full right then check for a minute or two then full left. On older biked the wires insulation ( plastic cover) becomes brittle and breaks allowing a short circuit. The head stock area has to flex every time you turn the bars to this is usually the first place they go.

Unfortunately its going to be trial and error to find it. May be worth considering a new loom or making one yourself

 

.....the reason I asked is that fuses are not generally intended to act as lighting devices; I would expect the conducting element to melt and fail long before the point of sustained incandescence being reached. I suspect that this fuse in the negative side of the circuit (shudder) is actually one of these LED types that light up when they fail. That is why I asked if normal service had been restored on replacement of the 10A fuse in the positive side. But I tend to agree.....sounds as if it's been messed about with so much that a replacement loom wouldn't be amiss. Unless, of course, it is repaired by a competent person.