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09 cb400 - dash doesn't even come on?

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by feldz, Jan 10, 2015.

  1. Hi guys,

    Two weeks ago I purchased an 09 cb400 - with a completely fresh battery (as of day I bought it). I was riding it around town today and I started it back up after a break, put my gear on, hopped on the bike and it just simply cut off. Unfortunately I had headphones in so I didn't hear any noises that could help diagnose the problem. Now when I put the key in (either of the two keys it came with), it's as if the key isn't recognised at all. The dash doesn't light up like it normally would, or the speedo and tacho don't flicker from left to right. Let alone be able to start it.

    Any help would be appreciated.
  2. Have you checked the battery terminals are secured? Could of worked loose if they weren't tightened sufficiently. If you have a multimeter that could help to get an indication of what the battery condition is. Also there could be bigger electrical gremlins in the charging system and the new battery wasn't the right fix.
  3. I'm thinking tommorow morning I will take the battery out and put it back in again definetely. I didn't originally put it in. I will also use a multimeter like you suggest! As a newbie to mechanical things though - I would have thought even if it was the battery, it should still be able to light up the dash etc even with low charge as surely that doesn't require much? and then fail when trying to start the engine (I don't get to this point). Also as it was running fine and then it just died makes me suspicious that it's not the battery. I hope it is though as i'm sure other electronics problems are $$$
  4. Kill switch? Lots of people have been caught by that before.

    As CBF'd said check battery terminal connections are tight. Then a multimeter to diagnose any further. Maybe the main fuse blown.
  5. Definitely not the kill switch made sure of that!
  6. To help eliminate the easy stuff, check that the earth lead from the battery to the engine is tight.
  7. So, quick little update. None of the fuses were blown and I don't have a multimeter but I hooked the battery up to charge. It was fully charged in about 5 minutes so i'm thinking it's not the battery. So it has to be something electrical which is failing to even turn on the dash when you turn the ignition key to 'on' ...
  8. #8 jmc, Jan 11, 2015
    Last edited: Jan 11, 2015
    I think you need a multimeter to confirm that the battery is ok. If it shows 12.6v with engine off its fully charged, but at 12.0v or lower its basically dead. If the battery is faulty or completely flat, it may not accept a charge.

    Faulty regulator/rectifiers are very common on hondas, if your RR is gone no charge will get back into the battery when the engine is running, and the headlight will run it flat fairly quickly.

    Your charged battery should read around 12.6 with no load and 13.x to 14.x with the engine running. If the battery voltage is not higher when the engine is running then the charging system is faulty (stator or RR). If that happens the bike will keep flattening the battery until the charging system is fixed.
  9. Thanks everyone for your replies. I appreciate it.

    Another little update. As it turns out it was the battery. I recharged it and put it in this morning and the bike started up.

    Something I didn't mention is that when I bought the bike, the owners had already replaced the battery (its an 09 model - 4000km) from the original one it came with, and when I went there to test it out that replacement battery wouldn't start the bike (after we'd turned it on once, it wouldnt start the engine twice). Long story short I bought the bike and ANOTHER fresh battery was bought and inserted, and now after 2 weeks this new one is having problems charging again?

    Am I correct in saying this is likely the rectifier?
  10. Most likely the charging system is faulty. Usually the RR is the culprit. On my CB600 it was a plug and play replacement, from memory it was located on the frame under the petrol tank on the right hand side.

    No amount of new batteries or recharging batteries will help you if the charging system is faulty, the headlight alone is a constant drain on the battery so they will just keep going flat.
  11. Grab a multimeter. A multimeter is only around $10 and is perhaps one of the most important tools for working on your bike yourself. If the battery reads above 12.6 volts it is charging. Ideally should be around 13. Best way of knowing what your charging system is doing.
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