[ihogan]

Well my ninja 250 wouldn't start so i jump started it from my car, i didn't know i had to have the car off. Well, it runs fine when jumped (tried it with car off, runs fine when jumped that way too) but once its off the jumper cables i don't even get power. what should i do?

 

[freightshaker]

Unlike jumping a car from a car The jumper car has to be off when hooked to the bike. After you jumpstart the bike it should run for awhile. First choice would be is charge the battery with a charger, but then we wouldn't be posting here now. If you're not getting juice to anything check the fuses. If the battery doesn't hold a charge then it's time for a new one.

 

[ihogan]

just checked the 30 amp fuse, its good. i'm gonna go get a voltmeter and check the battery. i should at least be getting the oil pressure and nuetral light to come on even with a somewhat dead battery though right?

 

[ihogan]

more info, when the bike was running by itself after i took the jumper cable off it was running horribly and the tach seemed to be polorized. at idle it would be at 11000rmp and when reved it would sound like crap but the tach would show the rpms go down.

 

[freightshaker]

A fully charged battery will have around 12.5 volts. When running the alternator should push 14-14.5. If not then your alternator is most likely the issue.

 

[ihogan]

when in the off position it has 12.2 volts. when i turn the key to the on position it drops to 0. dead battery or is something draining it?

 

[Silverfire]

The battery itself shows 0, or the connectors to it?

 

[ihogan]

the battery itself

 

[freightshaker]

Quick guess is it's either a short or that the battery could have a bad cell. It will show voltage but under any load it will drop.

 

[freightshaker]

The cheapest way to find out is charge the battery then do a load test on it. If you don't have one (battery tester) then most auto parts stores will do it for you for free.

 

[ihogan]

ok i'll start tomorrow by trying a new battery. i hope thats all it is, but that thing the tach was doing was really wierd i hope i didn't mess up my electrical system. would it do that if it was barely getting power from the battery? lights were also very dim.

 

[freightshaker]

It's very possible, like I mentioned, get your battery charged & tested. I'm thinking that's all it is. You did say it ran fine while it was hooked to another battery. If your battery is bad then the alt won't keep up with it. One other test you will need to do is test the output while running with a known good battery, then it should be around 14 volts.

 

[Silverfire]

If he's showing zero at the battery itself when under any load, then it's blown a cell, no doubt about it.

I used to work part time at a battery/alternator shop, and I've seen this a few times.

 

[ihogan]

threw a new battery in it, started right up!

 

[c_law23]

i did the same after draining my battery. i tried to jump from a car (the car was off) and it would start and when i unhooked everything it wouldnt keep. i threw the battery on a charger let it sit until it said it was charged...3 months or later the battery is like new.

 

[Jason C]

Lesson learned I hope. A battey tender only cost about 20 buck. Save yourself and pick one up. I had the same issue on my 84 Honda a few years back. The good tenders will let you know when something is wrong with your battery and eliminate all the worries.

 

[JimmyD]

Most bikes won't run on a dead battery for any length of time, even when jumped. You have to charge the battery for a minimum of a couple hours on 2amp before there will be enough juice in the battery for the bike to maintain.

 

[freightshaker]

threw a new battery in it, started right up!

Now just to double check, see that the volts are around 14 when running, if so you're good to go

 

[JasonFMHS]

haha, it would suck for a bad alterator to kill another batt. i'm with him... go head and check it in a day or two.

 

[serlant]

Sure its not that he had the car running when he jumped it that killed the battery?.