Battery won't stay working .......

I thought I had a flat battery so I linked it up to another to start it. Started fine but as soon as I disconnected the cords from the other battery, it just stopped working. It won't charge. Original battery 2 years old. Am I missing something else it could be?

you need to find out what the voltage is while running

It's not a big battery for all of the electronics, especially leaving the ignition switched on takes a toll.

Giggled the earth connector on the battery even though it is tight and she starts now. Can't tighten it anymore though so I have to fiddle with its position.

Rock Ape said:

Giggled the earth connector on the battery even though it is tight and she starts now. Can't tighten it anymore though so I have to fiddle with its position.

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As a general rule for grounds, when they are suspect it is always good to remove and do good wire brush cleaning of the contact points. Even a thin layer of grime or dirt can effect it negatively (no pun intended!!).
-MIG

Try doing this on the terminals, maybe corroded inside the connectors to the wire, I just put it in a plastic cup works great, then spray it dry with a little contact cleaner, GL I used it on my big connector on the instrument panel, looks like new, then they make a spray to keep it clean, on small connections use a lot of dielectric grease, I just don't use any on the injectors, hear it messes up the signal and I don't use any on the ECU, those are very well sealed anyway. But yeah you need a voltmeter to see what you have non start issues can be any connection in the starting circuit and ground, but a bad ground between the battery and motor will give you all types of trouble, even a dirty start button can be a problem, but I did that cleaning technique on all the connections I took apart looking for a fault in the instrument panel. And always disconnect the battery before disconnecting anything else, I blew my speed sensor out just by disconnecting and connecting with the battery hooked up. Maybe a spike or short, $150 mistake, don't make a $150 mistake

If the bike starts and runs with another booster battery hooked up then quits when you disconnect the booster with the engine running, you have a charging issue that needs to be addressed first before you condemn the battery. Now the charging issue could be associated with something as simple as a bad ground cable....

Dirt or oxidation on the battery terminal and/or the cable. Clean them with a wire brush or scrape them to remove the oxidation. Reattach tightly.

Another old trick is to screw a small screw in between the connector and the terminal. This provides a nice connection and an efficient pathway for the electrons.

I will give u a tip
If u don,t want to use a volt meter to check charging and clean terminals when they tow your bike be sure not to have the kickstand down it can break the block