Battery Electric Issue

My battery keeps draining power, when connected to the bike. Can anyone make any recommendations as to how to identify where the wiring earth/fault is?? I Have visually checked all the accessable parts of the loom.
T reg CB500s if that helps! Battery holds charge when not connected to the bike and alternator seems fine.

Any recommendations greatfully accepted. I have a multimeter - Just need to lesarn how to use it for testing!

Have you got any accessories (heated grips, alarm etc) that could be causing a problem?

Alarms have a bit of a bad reputation for this kind of thing... (especially cheap aftermarket ones!)

The simplest measurement you can make is the battery voltage - measure it once when the bike is off and once when you are revving the engine to about 4 or 5 thousand revs. Make sure the headlight is off when you do these checks.

The 'off' battery voltage should be somewhere between 11.5 and 12.5 volts, depending upon how recently you've ridden the bike and how charged the battery is. If the voltage is less than 11 volts then there is a problem, possibly you battery is dead.

The 'revving' voltage should be somewhere nearer 14.5 or 15 volts. If this is the case then the regulator rectifier is charging the battery correctly. You can also do a quick check by looking at the headlight brightness - it should get obviously brighter when you rev the engine.

If these mesurements seem OK then you should measure the current that is drawn from the battery when the bike is off, this is sometimes called the 'leakage' current. It should be very small (a few millamps). If it is not small you may well have found your problem.

If you want I can draw a quick diagram of how to connect your multimeter to make these measurements.......

No alarm, grips etc so I'll check the leakage. Have a feeling it might be high. Is it best to check it straight off the battery once it is connected ?

Yes, straight from the battery. Given that you haven't any extra electrical items connected I would think the current should be almost nothing when the ignition is off.

I had a moment so drew (a somewhat crap) picture and its here, for anyone who is interested. I think I got the name of the battery wrong, oh well, it doesn't matter...

I've recharged the battery and tested it to make sure it was holding the charge disconnectyed and all OK.
I connected the battery to the bike and hooked up the multimeter and you could watch the charge counting down!
I disconnected all the electrical connecters one by on and nothing seemed to stop the drop in charge.
Then I dsconnected the Earth? (red connector where the 30 amp fuse is) and the voltage on the multi meter actual went up. I disconnected the battery and retested it and it was back to a little under 12V.

What does this mean and how do I resolve the issue?

All help appreciated.

going by the wiring diagram you may have a starter motor relay short or a short in the ignition switch http://www.cb500club.co.uk/cgi-bin/download.cgi

i would disconnect the battery take off the wire at the starter motor then connect the battery then put your volt meter onthe starter wire (there should be NO voltage present) if there is i would suspect the relay

To measure the voltage and check when the voltage is going down is not very accurate and time consuming. I would suggest this method, using a multimeter:
1. disconnect the + wire from the bike battery
2. disconnect all bike power consumers (eventually take off all fuses)
3. connect an ammeter between + of the battery and red wire going to the bike (ammeter scale start from the 10A CC and systematic go down the range); careful to the polarity of the ammeter, connect the + of the device to the + of the battery!
4. insert the fuses one by one, one at time and see if you have some indication on the ammeter, eventually go down to the scale of the ammeter
5. if you see some indications on the ammeter check only the electrical circuit protected by that fuse
Hope this help,