Battery, regulator or alternator problem?

[Gunner]

Just bought a new battery 1 month ago. Everything has been running fine. Parked the bike since the weekend and fired it up today, only to find the bike clicking when trying to turn it on. At first i thought it was about to turn over but after a few more attempts it was only clicking and the lights were dimming. Used a charger to charge the battery and plugged it back in. Used a voltage multimeter and these are the values i got;

Sitting = 12.90 volts
Idle = 14.30 volts
start = 9.90 volts
RPM@4K= 13.95 volts

When i turn the bike off it starts at 13.40 volts and goes down 0.01 volts every 3 seconds till it equals out to 12.90 in about 4 minutes.

Read through a few forums but couldnt really find anything concrete. Any help on what the cause of the sudden dead battery be?

[FrugalNinja250]

Almost all the voltages you describe and the conditions upon which they occur are normal. The nominal battery voltage is 12V, that's inherent to the battery chemistry. Alternators and regulators are designed to put out around 13.5-14V under moderate load, sometimes a bit more (but never more than about 14.5V). When you first shut off the motor the voltage off the battery will show alternator voltage above, but that will rapidly decrease to the battery's nominal voltage.

The cranking voltage you measured is low. This can be caused by a defective battery or poor connections. I'd suggest disconnecting, cleaning, and reconnecting your battery connections. If they're fuzzy with old acid you can use a soft drink like Coke or Dr. Pepper to clean, then thoroughly rinse with clean water afterwards, or you can mix up a solution of baking soda and water to clean with, also rinsing thoroughly afterwards. Also, check the water level in the battery, if it's low you should return it for another one because it will likely be damaged internally from sitting with low electrolyte on the store shelf.

[Gunner]

Thanks for the quick reply!
Def will clean the connections to see if the running voltage will go up
but that doesn't solve the mysterious dead battery

[k-os]

Try going through this diagram to pin-point which component is faulty.

http://www.electrosport.com/media/pd...ng-diagram.pdf

[Motofool]

Originally Posted by Gunner

.........but that doesn't solve the mysterious dead battery

This reading may help you solve the mystery:

http://forum.motorcycle-usa.com/defa...?f=18&m=331125