A multimeter will tell you how much voltage it has ( you can take the caps off of each cell, place the NEG lead of the meter on the NEG post then put the POS or red probe in the electrolyte in each cell to see if you have a dead cell, each one should make your meter move about 2 volts, a 6 volt battery has 3 caps = 3 mini-2 volt cells connected in series, 12 volt has 6 caps ) but the only real way to test it is a load test to see how much current it can supply. If your Honda doesn't have electric start then the multimeter test described by oli will do. If it's bad replace it, or check the specific gravity of the acid/water in each cell with a hydrometer, it should be about 1.12 for a fully charged battery but this varies with temperature. Top up each cell with distilled water and put it on a trickle charger made for motorcycle batteries overnight, don't use an automotive fast charger or it may explode. Remember to wear cloths you won't mind getting holes in, goggles, and have plenty of water nearby to wash down with. Don't attept this on your signifigant others dinning room table.