just bought first bike, battery/charging problem

[carralo1]

Hey guys, new to forum, just bought an 02 gz250. The guy said battery is shot so we jump started it off his truck, everything worked all the lights I mean. Brought it home today and checked voltage of battery 4.7 volts. Jumped it off my truck and read voltage again while running and still 4.7 volts. Gave it some gas to increase rpms and still 4.7. So I aaume theres something wrong with the charging system. How should I go about diagnosing this or is it possible that its just that the battery is too dead... I assume not. Also when I checked out the bike two days ago the turn signals worked but today when I jumped it off they would come on a first which was weird and then when I hit the switch to turn them on, nothing. Also one last thing, when i had the cables connected to jumo the battery, when i went to take them off the battery on the bike, they were very! Hot. Any ideas?

[Skunkhome]

I think I would pull the battery off and charge it with a trickle charger over night and see what you get with it "fully charged".

[OldNTired]

Hey guys, new to forum, just bought an 02 gz250. The guy said battery is shot so we jump started it off his truck, everything worked all the lights I mean. Brought it home today and checked voltage of battery 4.7 volts. Jumped it off my truck and read voltage again while running and still 4.7 volts. Gave it some gas to increase rpms and still 4.7. So I aaume theres something wrong with the charging system. How should I go about diagnosing this or is it possible that its just that the battery is too dead... I assume not. Also when I checked out the bike two days ago the turn signals worked but today when I jumped it off they would come on a first which was weird and then when I hit the switch to turn them on, nothing. Also one last thing, when i had the cables connected to jumo the battery, when i went to take them off the battery on the bike, they were very! Hot. Any ideas?


Welcome, and congrats on the 'new' bike.
But, it sounds like you might have a short in the wiring.
Do as Skunkhome said, get that battery charged up first!
Then, get your meter and start looking for shorts and grounds. When running at 3000 RPM the system should be putting out AT LEAST 12.7V.
But, the high temp of the cables, assuming they are good, tells me that a LOT of current is going straight to a ground (a short). It'll probably take a bit of trial-and-error before you find it.
Keep us posted as you learn more about the problem, and we can help you more.

[mrlmd1]

Your battery is probably totally dead and most likely cannot be resurrected. Get a new battery and make sure you charge it up first regardless of what they tell you in the store, and try everything again. It's most likely your battery as the problem, not the bike's charging system. A totally dead/shorted battery will make cables hot and not let the battery accept any charge.

[carralo1]

Wow you guys are quick. This looks like a good forum and I will definitely be on here a lot. I will put in the new battery today and recheck everything and then post my results

[mrlmd1]

Be warned - make sure you charge it first or it will never hold a full charge and you will be back at the store getting a replacement real soon - like in 3 or 4 starts of the bike.

[carralo1]

Yes battery is in I charged it fully. Reads 12.5 before I started bike. While running it was at 13.6. Is that normal charging volts? Also the turn signals still don't work. What should I check on those. It was weird though cuz the came on again when I turned key to on position, but the turn signal switch was in the middle position and then when I go to turn them on (left and right) they dont work. Weird cuz they worked two days ago when I looked at the bike

[Skunkhome]

The charging rate sounds ok. As for the turn signals you might have a bad switch if it works intermittently. I suppose you are aware that the switch returns to the middle position when released but will continue to blink based on its last position. You have to push the button in to cancel the turn signal. Then again being your first bike you may not know that.

[carralo1]

Well this is my first bike I'm going to register, it's also the newest. I've restored a
Couple older 1970s yamahas. I did play with the switch and realized about pressing it in. It's not really intermittent because it's not working at all.... ?

[carralo1]

Electrical is by far my least knowledgeable... Lol.

[jonathan180iq]

Do you have a voltmeter that can test continuity?

[Water Warrior 2]

Electrical is by far my least knowledgeable... Lol.
There is no time like the present to learn. We will help you.

[carralo1]

Yes I have one that reads ohms and volts. Thanks for the help!!

[OldNTired]

Yes I have one that reads ohms and volts. Thanks for the help!!


First, try something easy. Get a can of electrical spray cleaner and clean the switch. See if that fixes it before we lead you through anything else. You might end up replacing that switch, but maybe the cleaner will help. If not, you'll have to check for power to the switch.
And since I didn't notice that anyone else answered your question, yes, it seems to be charging just fine. I think you said it was 13.5V; if the engine was running at about 3000RPM or higher that is right on.

[mrlmd1]

Did you ever sort out the turn signal problem? Just so you know, the turn signal goes on when you slide the indicator switch to one side or the other. They won't go off until you press the middle of the slide again. You may not have canceled them if you didn't press the switch. Read the owners manual for proper operating procedure on the bike, it will save you many questions.
And a fully charged 12V battery should read 12.6-12.8 V at rest. Do not try to charge up the battery by letting the bike idle for prolonged periods - first of all it will overheat and secondly, there is no significant charge output until at least 2500+ rpm.

[Meme]

Your turn signal problem may be just the fuse. Take off the seat and pull up the plastic storage box underneath. The fuse box is there. The fuse for the turn signals is the second from the left in the rear. It's a 15 amp fuse on mine. Test it or just replace it with a spare (there are spares in the box on mine) to see if it's bad.

[Water Warrior 2]

Also, in case you are unaware. The front signals are signals AND running lights. They use a 2 filament bulb #1157. The running lights are always on and the signals are just plain brighter. The rear signal is a #1156 single filament bulb and only signals.
Any Wally World or auto parts have lots in stock.

[carralo1]

Sorry Guys, haven't been able to work on bike. Spent the last two days redoing brake lines in my Camaro what a pita. Your help is awesome though. I'm gonna start easiest and check the fuse and then spray electrical cleaner inside switch. Then I'll post the results

[mrlmd1]

After checking all your bulbs and cleaning up all the contacts, check your ground wires too.