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Discussion Starter #1
Hi, if anyone could help me with this problem I would be most greatful. i have a 84' zx900 kawasaki ninja. At first, I thought the problem was an overheating problem which apparently is notorius with those models. but after much deliberation it turns out my relays for my main and starter connection are heating up and eventually stop functioning. There are 3 relays total; lights, horn and main. I bought a new relay and put that at main but it had no effect. When I'm riding, even if the temp of my bike is ok, after about 45 mins the bike will stumble and eventually just shut off completly. I then have to take the relays out and cool them off in my hand, once they are cool, the bike will start and run for another 15-20 mins and then shut down again.. I'm no expert, but I'm thinking there is a problem with the electrical system, maybe a bad ground or such. Why would these relays heat up to the point where they stop working?

cliff notes. electrical relays stop working because they overheat. wtf?

any insight would be appreciated. thanks!

dingle
 

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theres a hole in your theory. :wink: what makes you think its just the relays ? there are lots of things that could be getting hot and shutting down the bike. you need to check for spark when this happens. if your loosing spark then you have to start eliminating parts that control ignition. :wink:
 

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QKENUF4U said:
theres a hole in your theory. :wink: what makes you think its just the relays ? there are lots of things that could be getting hot and shutting down the bike. you need to check for spark when this happens. if your loosing spark then you have to start eliminating parts that control ignition. :wink:
ok, well after riding the bike hard, it will start to studder, if I hit the throttle it will die, If I just let it chug it will sputter for a few more blocks. It will not start up right away I have to wait a few minutes for it to even turn over. The reason I think it's the relays it because right after it dies the relays are to hot to even hold, and they are not close to the motor. I cool them off in my gloves for a minute, pop them back in and wham, back and running (for a little while at least). I just got a bottle of water wetter and plan on adding some tomorrow and see if that helps in any way or fasion, though I am doubtful..

How can I check to see if I have spark when it dies? If I hit the starter it does nothing, no turn-over, nothing.
 

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tha dingle said:
How can I check to see if I have spark when it dies? If I hit the starter it does nothing, no turn-over, nothing.
ah i c :D ok so it sounds like you have a wire rubbed thru thats grounding out and causing a the relays to take in too much current. i would start checking the wiring harness from the relays all the way thru looking for rub marks/bare wires etc.
i would also make sure the charging system is not OVERCHARGING. does the battery get really hot ?
good luck
:wink:
 

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Discussion Starter #5
QKENUF4U said:
tha dingle said:
How can I check to see if I have spark when it dies? If I hit the starter it does nothing, no turn-over, nothing.
ah i c :D ok so it sounds like you have a wire rubbed thru thats grounding out and causing a the relays to take in too much current. i would start checking the wiring harness from the relays all the way thru looking for rub marks/bare wires etc.
i would also make sure the charging system is not OVERCHARGING. does the battery get really hot ?
good luck
:wink:
I have never checked the battery. I will check that and look for wires that have a problem.. would it be easiest checking these wires using a volt-meter or just eyeballing them?
 

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tha dingle said:
I have never checked the battery. I will check that and look for wires that have a problem.. would it be easiest checking these wires using a volt-meter or just eyeballing them?
both would be good ways, since you wont be able to see INSIDE the wiring harness you may need to do voltage drop tests on some parts of the harness. youll need your service manual to see what wires go where.
good luck, electrical problems suck !!! :x
 

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Discussion Starter #8
Main Relay

Well, after a lot of playing with wires and connectors today I noticed that the relay will heat up even when the bike isn't running. Once I turn the key to the start position the relay will start to heat up. I disconnected the dash and turn signal horn connecters. I checked all wires for worn spots or corrosion, but no matter what I did the relay still heated up. As soon as I turn to start position I hear the relay click (dunno if that's good or bad) when the bike is running I can take the main relay out and the idle will increase a bit, which makes me think something attached to that relay is drawing a ton of juice. With the main relay out I loose all my guages and such, but the engine will keep running. One of the connections I messed with got my fan to kick on and off automatically (it had never done this since I bought it). Uhm. Any ideas? thanks

dingle
 

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ok so which relay gets hot ? whats it for according to your schematics ? find out and unplug it, if it doesnt get hot then you know what ever you unplugged is bad.
keep updates coming
 

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Discussion Starter #10
well it's definitely the "main" relay. The starter and lights relays are ok and not getting hot. I tried using the schematics diagram in the haynes book and that thing is like a maze and not making much sense. So I tried going about what you said logically, I started the bike and then unplugged the main relay and took note as to what stopped working. All the lights and guages and the fan. So I unhooked the guages, main still heated. Then I unhooked the lights (turn signals etc), still heated. The previous owner replaced the center stand so I removed the cross-over type plug he made for the kickstand sensor, still heated. At that point I ran out of things to disconnect. I will try again tomorrow and see if I can make sense of the schematics. thanks
 

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Discussion Starter #14
Yup, the main relay in the fuse box is the bugger getting hot, and when I say hot I mean after 45 mins its so hot you can't grab it with your hand.
 
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