I just replaced my battery, it hadn't been getting enough charge on the trip to work (7km)to start, and I've been bump starting it to get home.
Most embarassing thing I ever did on a bike was on my old 250 Yamaha dirt bike while I was still at school (1974). Rolled down the hill from home, put it into 2nd and dumped the clutch. Nothing. Tried again. Nothing.
Then I remembered I'd taken the chain off the night before to clean it! Long push back up the hill.

Just took a closer look at the battery.  Been on the charger (0.5 amps) for seven hours now.  There are some bubbles rising up from the plates...but the battery itself is cool to the touch, and none of the electrolyte has evaporated.  Is this normal?

EDIT:  Is this just the hydrogen gas produced as a normal part of charging?

Perfect sounds like it is charging correctly and yes it will produce gas doing this. Not sure what gas but this is why the battery is vented on the side to release the excess gas produced.

Now that you have done this take your multimeter and get a reading with the charger on, then if you can without taking the leads off disconnect or turn off charger and watch for the Voltage drop. A good battery should hold around 12.9VDC. Thats good if it does. If it does then turn the key on and check the voltage again. It should drop slightly and then hold at some point. Hopefully it will hold at +/- 12.0 VDC for more then 5 minutes. If it ever drops significantly below at any point or never levels out then the battery is shot! Go buy new one and stop waisting your time.