No Electrical & Melting Cables

[ndmuscutt]

I have had a recurring problem with my GZ250 for the last year and a half. It's left me not able to use it and, now and then, I can find time to try and figure it out.


Just replaced the solenoid, hoping it was the problem. When the ignition is in the on position, occasionally the headlight will come on and the bike will turn over. Usually it doesn't. There is zero electrical.


Today, I put the jumper cables from the battery to the car because the battery (for some reason) was only at 7 volts. So I put the cables on to jump the bike and the cables began to smoke. I quickly checked to make sure that I had + to + and - to -. No problems there. Hooked the cables back up. And they started smoking and actually melted the plastic. The headlight was only faintly on and the bike still would not start.


I am at my wit's end with this thing. Any suggestions?


By the way, the problem all started last year. When I was riding down the road, the bike would just stop. Blowing the main 20A fuse. Sometimes it would go 5 minute between blowing the fuse. Sometimes all week. It's not blowing the fuse anymore. It's just got no electrical at all now most of the time. Thanks.

[derbydave]

Short to ground somewhere. Check all the wires for melted or chaffed insulation. including inside the headlight bucket. Disconnect the starter and test to see if the problem still exists.

[alantf]

When you jumped from the car, was the car engine running? If it was, the high charging current of the car will fry a bike batterry. You should always jump a bike with the car engine off.

[ndmuscutt]

Originally Posted by alantf

When you jumped from the car, was the car engine running? If it was, the high charging current of the car will fry a bike batterry. You should always jump a bike with the car engine off.

Thanks, guys. I have taken a preliminary look over some parts of the wiring but have not found anything suspicious yet. I will take a closer look when I get a chance and do some follow-up.


However, in regard to the charging current being too high from a running car, how can this be true? You can't force current into something. The battery has to be drawing the current. I'm not an electrical physicist, but won't the battery only draw what it's able to draw?

[alantf]

Let's try to liken this to your house wiring. The cable on any circuit will only take a certain current before it overheats and melts, so you put a circuit breaker (same thing as a fuse, but resettable) in the line, that blows before you get a dangerously high current. Same thing with a bike. Suzuki recommend 0.75A to recharge the battery. A car battery is designed so that to start the engine, it uses a high current from the battery. Once the engine is running, the alternater shoves a high current into the battery to get it fully charged again. If you jump your bike with the engine running, the high current will shoot across, heating everything up, frying the battery, and possibly melting the cables of your bike, that aren't designed to stand them.
Hope this helps explain this. Until I retired, I was an electrician for 50 years, so I can assure you that jumping a bike from a car with a high charging current WILL fry your battery.
Remember, power = volts x amps, so in America, at 115v, for any given power, the cables have to be twice as thick as European circuits at 240v. Transfer this thought to your bike.

[blaine]

Will also fry the ECU.Many of us have learnt this the hard way....That's why we post on here.....So others can avoid what we already experienced/know.

[ndmuscutt]

Originally Posted by derbydave

Short to ground somewhere. Check all the wires for melted or chaffed insulation. including inside the headlight bucket. Disconnect the starter and test to see if the problem still exists.

Guys, I'm very sorry that I've taken so long to get back to this thread. Life's busy and my bike looks pathetic in the driveway all torn apart.

Anyway, it's been a week or so since I've looked at it. Here's what I did just now:

1. I disconnected the battery terminals from the bike's leads. Then I connected jumper leads from the car battery (car not running, thank you): Black to the bike's ground. Then red to the starter lead (negative side) of the bike's solenoid. The bike turned over.

2. I then connected the positive to the positive side of the solenoid. The headlight came on full and the bike had electrical. Hit the start switch and the bike turned over. Was very happy about this. So, I turned it over again and suddenly it just quit completely. The strange this was that the headlight went to brown-out (half-lit).

3. Disconnected the positive lead from the positive side of the solenoid and put it straight to the starter, with black on the bike's ground. Got a huge spark and the positive lead welded instantly to the starter terminal, smoking and I had to tear it off.

So, I'm not a good electrician, but I'm going to venture a guess: The short is in the starter and the starter needs to be replaced. The starter will turn over a couple times if it's cold. But after it gets a little heat, something inside shorts. That's my guess. But I'm only guessing. I'm all ears for your input.

Thanks guys.

[derbydave]

Originally Posted by ndmuscutt

So, I'm not a good electrician, but I'm going to venture a guess: The short is in the starter and the starter needs to be replaced. The starter will turn over a couple times if it's cold. But after it gets a little heat, something inside shorts. That's my guess. But I'm only guessing. I'm all ears for your input.

Thanks guys.

It sounds like to me you found your culprit. I would remove the starter and bench test it. You should be able to tell if it shorts or draws excessive current.

[ndmuscutt]

Originally Posted by ndmuscutt

Guys, I'm very sorry that I've taken so long to get back to this thread. Life's busy and my bike looks pathetic in the driveway all torn apart.

Anyway, it's been a week or so since I've looked at it. Here's what I did just now:

1. I disconnected the battery terminals from the bike's leads. Then I connected jumper leads from the car battery (car not running, thank you): Black to the bike's ground. Then red to the starter lead (negative side) of the bike's solenoid. The bike turned over.

2. I then connected the positive to the positive side of the solenoid. The headlight came on full and the bike had electrical. Hit the start switch and the bike turned over. Was very happy about this. So, I turned it over again and suddenly it just quit completely. The strange this was that the headlight went to brown-out (half-lit).

3. Disconnected the positive lead from the positive side of the solenoid and put it straight to the starter, with black on the bike's ground. Got a huge spark and the positive lead welded instantly to the starter terminal, smoking and I had to tear it off.

So, I'm not a good electrician, but I'm going to venture a guess: The short is in the starter and the starter needs to be replaced. The starter will turn over a couple times if it's cold. But after it gets a little heat, something inside shorts. That's my guess. But I'm only guessing. I'm all ears for your input.

Thanks guys.

OK. So, an update once again.

I took the starter out and bench-tested it from the car battery. Ran just fine. Didn't appear to have any shorts. I hate these dead-ends. So, here's what I did next.

1. Tested for continuity between the bike's positive terminal lead and the bike's ground. There was continuity. Hmmm. . .

2. Tested for continuity between the positive and negative terminals on the solenoid. Yes. Continuity. Crap.

3. Tested the bike's battery voltage. Just curious. 6.8 volts. Crap. Somehow the battery must have gotten fried.

4. Connected the jumper leads to the bike's positive and negative leads. The starter clicked like it was trying to turn over without the key being on.

So, here's the thing. I just replaced this solenoid. This is a new one. Is it possible that it's stuck in the closed position?

Now the other thing that's really puzzling me is that, in my last post, you can see that the solenoid seemed to work just fine! And when I put the jumper right on the starter, that's when the cables started smoking. Putting this post and my earlier post together, I'm really stumped.

Again, I'm all ears.