Author Topic: Sparking negative battery cable (Read 14025 times)

jessez · « **on:** March 30, 2014, 05:53:24 PM »

Hey guys
I have a 92 k75s that I stored this winter with the battery out. I kept a charge on the battery all winter and it reads about 12.6v before hooking it up to the bike. I tried to put it in yesterday, putting the positive on first. When I touch the negative cable to the terminal it sparks big time, so I've only dared to touch it to the post briefly a few times. A couple of times the starter motor engages (the key is not even in and the key position is off) which is very unsettling. One thing I want to make sure is that I'm not reversing polarity (what I believe is the positive is a bundled set of three wires that head toward the engine block and what I believe to be negative is one solid large gauge wire that appears to bolt to the left lower frame). Assuming I am correct with that, I am unsure what to look for besides noting that neither of those cables appear to have any damage to the insulation and the terminals are quite clean. I hope I didn't do damage to the bike.

Zipster · « **Reply #1 on:** March 30, 2014, 06:18:44 PM »

I'm no expert but if it sparks there must be some sort of draw on the power. If your bike is anything like my K1100, the battery is isolated when the key is turned round so that the steering lock is engaged. The last time I had my battery out when I was replacing the ABS 2 modulator, I had the steering locked so there was no drain and therefore no sparks.

jessez · « **Reply #2 on:** March 30, 2014, 06:33:01 PM »

Zipster, I'm hesitant to think that is my issue; I've never locked the steering in the 4 years I've had the bike and have taken the battery in and out many times with no sparking. In fact I don't really know how to lock the steering. Also I noticed when touching the negative cable to the post, the clock doesn't even flicker which I also find alarming.

johnny · « **Reply #3 on:** March 30, 2014, 08:55:51 PM »

id putts a volt meter between the battery post and that unattached cable and see whats you gotts...

j o

Inge K. · « **Reply #4 on:** March 31, 2014, 06:42:06 AM »

It sounds to me that you got welded starter relay contacts, quite common on old K's if you doing starting attempts with a weak battery.

Often you can free the contacts with a few gentle knocks with the rearside of a screwdriver on the outside of the relay, the relay you find at rear RHS in the relay box.
You could first try a few knocks on the outside of the relay box, at that particular spot...you might be lucky, less work.

If you don't have succes with any of the above mentioned metods, the relay can be opened....free the contacts and clean them with some fine emery paper.

jessez · « **Reply #5 on:** March 31, 2014, 06:11:43 PM »

Thanks Inge, I'll try that this week and post the results.

jessez · « **Reply #6 on:** March 31, 2014, 08:39:52 PM »

Sorry to be a pain guys. I wanted to look at the starter relay, and it's located in the electrical component box under the fuel tank. Is there any way to slide the box out without taking off the fuel tank? I'd hate to take the tank off if I don't have to since it's full of gas and since it seems pretty labor intensive.

TimTyler · « **Reply #7 on:** March 31, 2014, 09:11:18 PM »

Taking the tank off is super easy if you don't have a fairing blocking the fuel hoses. 5-minutes max.

loosen and remove the tops of the two fuel hoses (forward-left bottom on tank)
slide out the two clips with needle-nose pliers (rear bottom tank)
disconnect the fuel pump power connector (right rear tank)
lift rear of tank straight up with some effort
slide tank backwards and off bike

mystic red · « **Reply #8 on:** April 01, 2014, 07:38:45 PM »

It's a 2 minute job even on a LT......

Scott_ · « **Reply #9 on:** April 01, 2014, 10:38:47 PM »

Quote from: mystic red on April 01, 2014, 07:38:45 PM

It's a 2 minute job even on a LT......

Even if you still have the jesus clips still on......... not that there's that many left installed yet. :hehehe

jessez · « **Reply #10 on:** April 03, 2014, 08:34:13 PM »

I'm going to take the tank off Saturday. Would it help me to drain it completely first or is it no big deal to remove the tank full of gas?

WayneDW · « **Reply #11 on:** April 03, 2014, 09:09:31 PM »

Quote from: jessez on April 03, 2014, 08:34:13 PM

I'm going to take the tank off Saturday. Would it help me to drain it completely first or is it no big deal to remove the tank full of gas?

Gas in the tank is no problem. Just disconnect and lift. One hand in the front, one in rear, keep it level. Rear up first then slide the tank slightly back as you lift.

Motorhobo · « **Reply #12 on:** April 03, 2014, 10:15:34 PM »

The hoses will drip some when you disconnect, have a good sized rag handy.

subforry · « **Reply #13 on:** April 04, 2014, 12:00:53 PM »

The less gas the better simply because the tank will be lighter. A full tank has about 44lbs of gas.

jessez · « **Reply #14 on:** April 05, 2014, 09:29:08 PM »

Thanks to everyone for the help. I had the gas tank off in a few minutes (found out one tank clip was not even there) and got to the starter relay. I've removed the relay and the contacts where it is plugged in looks fine, as does the contacts where the red and black leads attach. Should I take the relay apart to see inside or is there a continuity test I could check?

Inge K. · « **Reply #15 on:** April 05, 2014, 09:43:18 PM »

Have you tried to give the relay a few gentle knocks, as mentioned in reply #4?

You can measure between the two heavy terminals when the relay isn't connected,
it should be a open circuit when the relay is OK.

jessez · « **Reply #16 on:** April 06, 2014, 08:05:16 PM »

Wow, hitting the relay with a screwdriver somehow magically worked! Thanks for the advice. I wonder though if I should replace the relay or buy a new battery to stop this from happening again.

mystic red · « **Reply #17 on:** April 06, 2014, 08:16:14 PM »

Huh, Inge K. actually knows a thing or two. :giggles He's forgotten more about K bikes than I know. I think you can take it apart and clean contacts but I have never done that. Low battery is usually the culprit.

Scott_ · « **Reply #18 on:** April 06, 2014, 10:56:29 PM »

Quote from: jessez on April 06, 2014, 08:05:16 PM

..... I wonder though if I should replace the relay or buy a new battery to stop this from happening again.

Well, even if you replace the relay, and keep a week battery you will just be asking to weld the contacts again and be right back to where you are now.

jessez · « **Reply #19 on:** April 07, 2014, 07:48:40 PM »

That makes sense. I guess a better question would be: Provided I put a new battery in, will my once compromised relay be prone to failure?

Scott_ · « **Reply #20 on:** April 08, 2014, 06:57:36 AM »

Some owners have opened the relay and 'dressed' the contacts and been able to save the relay and reuse it with no ill effects.
Some have just "unstuck" it, put in a fresh charged battery and have been perfectly fine also.

If you decide to dress the points, don't use regular sand paper. It is prone to leave sand bits behind.
A good quality machinist emery cloth would be better. something fairly fine 320 or better, and don't over do it. just remove the rough spots.

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Author Topic: Sparking negative battery cable (Read 14025 times)