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Discussion Starter #1
Hi

My 2006 Brutale has 23,000km and has been running flawlessly. A couple of days ago, I turned the ignition on and the instrument display lit up normally. I started the motor but the battery charge warning light stayed steady on. I revved it a few times and also took it for a short run around the block but still on permanently/no flickering. The bike has a new battery and I gave it a charge overnight. Today did the fault checking as per the manual at Sect E pp12-19. Checked/cleaned the 4-way connector, earth leads, battery terminals and all fuses including the 40A recharge fuse. With ignition on but motor not running, the voltages at the 4-way connector are: pin1/S terminal=12.68V; pin2/lg terminal=12.62V; pin4/L terminal=11.61V and B terminal=12.78V (same as at battery terminals). I plugged the connector and put everything back to normal, however, with the motor running, the charge warning light is steady on and the voltmeter across the battery terminals is only 12.4V and doesn't change when revving the motor.

I've got a bad feeling that it's the alternator...

I'm a reasonable home mechanic and have got most if not all the tools I'll need...a few questions:
- the manual says that the generator/alternator and the IC Regulator/rectifier is enclosed in the one component. Is this correct or is the 'IC Regulator' somewhere else eg the SPU unit?
- can the alternator be worked on and parts such as brushes/diodes/the IC regulator unit be bought/replaced?
- if I were to work on the alternator, it looks as if i'll need to drop the motor out of the frame. How difficult is this? Any special things to watch out for etc?
-any suggestions of where I might source a complete alternator/IC regulator unit both new or second-hand?

any suggestions much appreciated, cheers Claudio :bawling:
 

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Hi Claudio! The alternators can be worked on and rebuilt. If you search, probably in Maintenance, you will find a description of alternator removal, although it is for an F4. The workshop manual, I haven't checked will probably describe the process in detail.

Since you just replaced the battery and then the problem appeared, make sure you got ALL the wires hooked up to the proper battery terminals before you go tearing things apart. Many an issue has been caused by battery replacement because of things like revers polarity and not getting all the leads back on.
 

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Discussion Starter #4 (Edited)
hi guys

thanks for the replies. I should clarify that when I said new battery, I should have said that I replaced the battery only 3 months ago. The bike's been running perfectly since then.

Just now remembered that I cleaned the bike with detergent/water and then lightly hosed it down last Thurs. I didn't start the bike then but the problem appeared the following day when I tried to start it. While washing the bike I tried to avoid squirting the hose directly into the motor/alternator area but seems suspicious...hmmm...post hoc ergo propter hoc aka suspicion of cause and effect....I would have thought that any moisture/water droplets in the alternator innards would have dried out by now

I did check for tightness both the battery terminals and the ground wire/earth terminal on the motor. I'll go over it again by undoing the bolts and cleaning everything just in case some corrosion has got in there

tnx and cheers, Claudio

PS just spotted the other post "Alternator Diagnosis Suggestions" http://www.mvagusta.net/forum/showthread.php?t=54752 and will check out those suggestions tomorrow
 

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Check out this thread Claudio

http://www.mvagusta.net/forum/showthread.php?t=35119&highlight=regulator

I took my alternator to a few auto leckies and none of them wanted to touch it because it was out of a bike. I found one who was preparred to at least look at it, I printed that thread out for them as a guide, but they ended up saying they couldn't do it. Thing is, it's a denso alternator and it physically looks identical to the alternator on our toyota forklift. I think auto sparkies just want to change batteries and light bulbs these days.

So, as that thread shows, it can be done....you just need to find a tradesman who is preparred to have a go.
 

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Discussion Starter #6
an update...today cleaned/de-oxidized all the grounds/fuses/etc. From batt negative i'm seeing less than 0.01ohms when touching alternator/starter/motor/frame so no resistance there. Still only get 12.5V across the batt terminals with motor running at various revs.

Looks a faulty alternator/regulator eg Sect E p16 an open circuit at the rotor coil probably the brushes.

Some questions:
- can the ECU diagnostics error codes give a detailed indication of my alternator/regulator fault?
- to remove the alternator do I have to take out the motor from the frame?

cheers, Claudio
 

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There are some instructions somewhere here for removing the alternator without having to remove the engine from the frame, I believe the trick it so remove the starter motor but never actually got round to doing it myself.

If you need an alternator I have a nearly new one I bought to put on my 750 but no longer need it.
 

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Discussion Starter #8
I took my alternator to a few auto leckies and none of them wanted to touch it ... I think auto sparkies just want to change batteries and light bulbs these days.

So, as that thread shows, it can be done....you just need to find a tradesman who is preparred to have a go.
Damn...that could be tricky in ole' rainy/cold Adelaide

Reading the other thread made me feel even more depressed..looking more and more like i might have to take it to the local dealer and pay through the nose so I can get my bike running again some time soon....the only upside I can see is that I can keep the dudded alternator and try repairing it so that i have a spare, maybe..

thanks for the info
 

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Discussion Starter #9
There are some instructions somewhere here for removing the alternator without having to remove the engine from the frame, I believe the trick it so remove the starter motor but never actually got round to doing it myself.

If you need an alternator I have a nearly new one I bought to put on my 750 but no longer need it.
Yeah, i saw that at Sect E, pp32-33. That's what I was wondering...if it's possible to get the starter motor out it might be possible to get the alternator out too...anybody?

Ur 750 alternator sounds good...would need to be sure that it fits my 910S?
 

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Yeah, i saw that at Sect E, pp32-33. That's what I was wondering...if it's possible to get the starter motor out it might be possible to get the alternator out too...anybody?

Ur 750 alternator sounds good...would need to be sure that it fits my 910S?
Yep, pull the starter motor, and if you jiggle the alternator down and foward, and hold your toungue just right, it comes out. I think the the other thread quoted above shows a minor mod that allows you to get it back in much easier.

EDIT: It's this thread - http://www.mvagusta.net/forum/showthread.php?t=48597&highlight=alternator+removal

I got a second hand alternator from a 750 F4 and all the numbers were the same.....I am 99.9999% sure all the alternators from the earlier generation bikes are the same.

Don't be put off by my lack of success finding someone to fix mine, it says more about the tradesmen than it does about the alternator.
Just keep trying 'til you find someone.....I didn't have the time as I was taking the bike on a trip and had to get her running asap.

Good luck!
 

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Take the whole alternator to a decent auto electrician, they should be able to fix it. Otherwise ebay for a complete secondhand one.
 
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