Hi all. So my bike was working just fine, then I went to a park, turned it off, and left it for about half an hour. When I came back it wouldn't start but it kept turning. Eventually it stopped turning, started clicking, and wouldn't start without a jump. I just replaced the battery so the only thing I can guess is the alternator? Help please?

 

You don't say which bike you have, but if it started ok at first then it seems that your battery isn't being charged properly. Charge the battery overnight and check the voltage next morning. It should be14.5 volts or a bit more. If the bike starts ok, then check that the battery is getting a charge by connecting a multimeter set to direct current across the two battery terminals. The voltage should be over 13.0 volts and rising as you rev the engine. If you don't see an increase and the voltage starts to drop then your alternator isn't charging properly. If the voltage is over 14.5 volts, then the rectifier is faulty and is letting too much charge from the alternator get to the battery and may have damaged it. If your own battery won't start the bike after the overnight charge, then try starting it from a decent battery with jump leads. If it then starts then your battery is probably damaged and needs a proper check at your local garage who will usually do this for free. There is a section on this forum all about checking the charging system if you need more help.

 

Sorry. My bad. It's a 1997 900rr. It started just fine at the beginning of the day, Then it just didn't turn at the park. It was the weirdest thing because the only time the damage could have been done was within that half an hour window.

I forgot to mention this. Maybe it would help. It wouldn't even start and I had to get it home. So I took the fuse for the headlights out. I then hooked my battery up to a running car, left my bike off, and that gave it enough juice to start and get me home.

I don't have much experience with the electrical system, so allow me to ask a couple questions.

1. Could you briefly explain how to properly charge the battery? (Or link me to that aforementioned section on the charging system if it's in there)

2. When I check the voltage after that initial overnight charge, I just take a multimeter and put a probe on the positive and negative terminals?

I will charge it today and come back with what I find. Thanks again. The help is much appreciated.

 

K. I'm back with my findings. I started my bike then unplugged both battery terminals. My bike would continue to idle but it wouldn't do a damned thing when I touched the throttle. It would just sputter then die. Which leads me to the conclusion that the problem lies in my alternator. I think that it is dying and can only supply enough power to keep the engine idling. Is my logic sound? How do I go about replacing my alternator?

 

Charging System Diagnostics - Rectifier/Regulator Upgrade - Triumph Forum: Triumph Rat Motorcycle Forums

Check this thread, it will help you narrow the problem down.
Ern

 

Not sure why you disconnected both battery leads once the engine was started, 'cos the engine will die! You say you got it started with another battery so do that again and, leaving the battery leads attached, put the mulitmeter leads on the positive and negative terminals on the battery, rev the engine and watch the multimeter gauge to see if the voltage rises to around 14.5 volts. The alternator is there to keep the battery charged and the rectifier is designed to change the alternating current from the alternator into direct current which charges the battery. Use the trouble shooting section on checking the charging system to find a permanent solution.