Johnny Law gets Busted

[Hot Pursuit]

Hello fellow Kawi Riders -

I was wondering if anyone had any ideas @ a problem I'm having w/ a 1989 KZ 1000 Police Special. The main symptom is a Main Circuit fuse that gets so hot over the course of just 15 minutes of riding (it's to hot to touch after just 2 minutes of warm-up) that it melts the solder & 'blows' the fuse.

Obviously, the problem is in the electrical system. I have replaced the voltage regulator, ignitor & battery. I have inspected (& found to be fine) the ignition switch & starter motor. This occurs when all of the 'police switches' are in the off position (or on, for that matter). Since none of the other circuits get hot & the battery holds a charge for weeks: I'm assuming there is some sort of short in the main circuit after the ignition switch. Any weak points to check? Any tests to run?

Am I headed in the right direction? Does anyone have any insight? It's a great bike in all other respects & I'd hate to see it burst into flames @ 75 miles an hour (Especially w/ me astride).

Thanks for any help.

[bikeaholic]

know if its ever been repaired before?

is the wire the right gauge?

[Hot Pursuit]

The wiring harness is relatively un-butchered, but the bike's definately been worked on before. The wiring to & from the main fuse/ ingnition switch appears to be the original heavier guage (White, White/Black)still in the factory wrap/tape. I found a hot unswitched lead (probably from the rear police lights/equipment) rubbing against the frame beneath the battery box. But the melting fuse problem continues as it has from the begining.
I can't see any signs of melted wiring in the visible portions of the harness. The only thing (electrically) that had been done since the bike was purchased was to rebuild the starter motor. Could this be the culprit? All other electric functions work perfectly (lights, self cancelling turn signals, horn, guages, etc.).

thanks for your help.

[ZX Kawboy]

Check the stator output.

it's not at all uncommon for Kawi police bikes to have a higher-put stator installed in order to keep up with the greater demand on power. When you've got lights, an onboard computer, a radio, and various other odds and ends (such as heated riding gear for the cooler months...and yes, they have that too) it draws a great deal of juice.

As a result, it can cause your electrical system to run 'hot'...that is....for the alternator to put out more power than it needs, after all that stuff is removed.

Also, it wouldn't hurt to check that *all* of your grounds are making proper contact. if even one isn't right, you'll get a hot spot, such as you've described.

Get a manual for the thing,and chase down the electrical system, testing everything in sight. Make sure it's all 'right', and replace/repair whatever isn't.

That should do the job. Keep me posted with the results?

Spoone

[Hot Pursuit]

thanks for your input.

I know faulty grounds are 90% of most problems like this in a common ground system. I was trying to save tearing open the harness til last. I have already started doing just what you said (re ; manual + wire chase) but didn't consider the high output stator. If all checks out & the bike still blows fuses - whats the fix? I'm assuming it's a high amperage output (the voltage regulator should still do its job) that's causing the problems. I wonder if wiring all the lights to constant on (currently running single switched headlight & aux. fairing lights disconnected) would help?

I'll let you know how the hunt goes.

[kelletx]

I just replied in the "MECHANICS CORNER" section of your original post.

I originally thought the same thing about the HIGH OUTPUT STATOR possible causing the fuse to melt, but I would think that if its a HIGH AMPERAGE problem, the fuse would "blow" "normally" once it went past 30 amps.

I don't claim to be a mechanic or an electrical expert...I'm just assuming that 30 amps was the design limit of the system and the fuse should "blow" when that electrical limit was reached.

The thing that's so weird about this problem is that the fuse gets so HOT that the solder inside the end of the fuse actually MELTS and it disables the fuse...it doesnt "short" the actual fuse part that you can see inside the glass tube...that's always intact.

After examining the old fuse block that I just removed tonight I'm hoping the solution will come after checking the wiring digram to see where that solid white wire goes. There maybe a bad ground on that other end or ...who knows?!

As far as your idea about running the electrical accessories "always hot", our experience is that the fuse "melting" happens when NONE of the emergency equipment is turned on, just the headlight. That seems to support your idea but the whole problem doesn't make sense to begin with! arrgggg

Any other ideas are welcome! thanks

[moparman]

Heat in wiring usually comes from higher amps than the wire can support (or higher resistance in the wire than the amperage needs). That said, I would trace the main wire from end to end if that is the only one heating up. If you find nothing wrong, maybe replace it with a bigger gauge and see what happens. It is also possibly needing a bigger ground cable off the battery.

[Lee_2061]

The ground will not be a likely culprit as the return from everything can be thru the wiring or the chassis. A fuse getting warm enuff to melt the solder means the current draw is too high. It's possible the fault is an active or positive lead being grounded. This happens because of one of the following.
one of the circuits from the ignition to a device has worn insulation,
one of the switches has an internal short to ground,
one of the connectors has a short to an adjacent wire.

If you can isolate the circuits, usually at the main connector cluster or the fusebox, you can try using a multimeter to trace the fault.
Measure the current draw in each circuit. If the wattage (Ampsx12V) is higher than the power consumption of that device, be it a lamp or a fan, you have your short circuit.
Alternatively you can disconnect the earth/negative from each circuit and see if the circuit is still being completed. It shouldn't be unless there is a short. You'd need to disconnect the battery terminal first before doing this.

[jono]

I had similar problems with my KZ650, it was just the connectors being rusty. The final one was in the headlight assembly. Id bet money that its that, or a faulty switch, like the horn....( that happenned to my spectre.)