MV Agusta Forum banner

1 - 20 of 28 Posts

·
Registered
Joined
·
890 Posts
Discussion Starter #1 (Edited)
today on the race track, the red light indicating the battery is low on voltage turned on. first, just for a few seconds, but then stayed on.

tested the charging voltage from the alternator and it is just zero.
apart from a broken alternator, could there be anything else wrong
with the electric system? any fuses, which may have gone?

fast help would be appreciated, as i have booked two
additional days on the track, and dont want to miss some
obvious flaw.

Edit: it is a F4 1078 312 RR
 

·
Registered
Joined
·
1,216 Posts
Assuming the charging system is he same as older F4s, there's a 40 Amp fuse under the left side fairing, above where the water pump is. There's also a spare in there.

Si

Edit: page E-36 in the 750 workshop manual, don't know about later ones.
 

·
Super Moderator
Joined
·
22,072 Posts
Ah Shit mate

That is horrible, did you check if you did not just have a plug come out somewhere ?
If you have a charger to charge the battery between sessions, you might get 10 or 12 laps out of the battery.

Damn that's a terrible thing to happen to you man. Hope you get sorted.
 

·
Registered
Joined
·
890 Posts
Discussion Starter #6
thanks donsy.

yes, it is my plan to just charge the battery and
at least get a few laps out. and if i am lucky i
will get a spare alternator from a 750.
 

·
Registered
Joined
·
1,511 Posts
Check the wires that attach to the alternator, i found a lot of rust corrosion on the connector, cleaned it up and all was ok.
jimboF4
 

·
Registered
Joined
·
890 Posts
Discussion Starter #8
with a lot of luck and fortuity, i got my hands on a spare
alternator. it is charging now again, and i am looking
forward again. now just the rain has to stop ;)
 

·
Super Moderator
Joined
·
22,072 Posts
+100

with a lot of luck and fortuity, i got my hands on a spare
alternator. it is charging now again, and i am looking
forward again. now just the rain has to stop ;)
Awesome, hope you have a good weekend HP :yo:.
Looks like everybody is having rain, we too are scheduled for rian 2'morrow.
 

·
Registered
Joined
·
890 Posts
Discussion Starter #11
final update: bike works perfect again with the new
alternator, and could enjoy a fanastic track day.

the only little "bug" remaining is that on idle the red light sometimes
is still on, but as soon as the engine is reved it disappears.
 

·
Registered
Joined
·
890 Posts
Discussion Starter #13
I suspect you will be up for a new regulator soon, those poor old diodes probably got a good voltage spike as the alternator fried itself.
good point. i contrast to many sports bike, the regulator and
alternator on the MV are one piece. i suspect the cooling for
the regulator is actually pretty poor. so i replaced the full piece
at the moment, and will later test, whether the failed part
was the regulator or the alternator. and your right, a failure
of the diodes in in the regulator is much more likely.
 

·
Registered
Joined
·
1,260 Posts
I'm chasing an intermittent red light recently and I doubt Carl is going to give me my money back after at least 5 years of using the alternator he sold me :naughty:
Bloody thing is ALWAYS working as I pull into the garage so I haven't been able to test anything much yet...

I've checked all the wiring/connectors, removed and cleaned the two earth straps to the valve cover and the back of engine/gearbox casing, are there any more ?

Also installed a new starter solenoid ( thanks Joe!) as mine had suffered some melting and corrosion of the contacts - the fuse plastic was mostly melted :jsm:

The alternator appears to be working still even when the red light is on as the headlight still gets that little but brighter as the rpm increases from idle....

Is it likely to be anything other than the regulator before I pull the whole thing apart ? And has anyone ever managed to get the regulator repaired rather than replacing the whole alternator ?

Cheers
Rich
 

·
Registered
Joined
·
890 Posts
Discussion Starter #15
Is in your situation the red-light always on? or it just
sometimes on/off during riding?

what is your voltage at the battery? maybe the alternator
just does not manage to have a high enough voltage for
the charging.

here are mine values as refereces:

battery voltage: 13.2 V
bike running without alternator: 12.5 V (red light on)
bike running with with new alternator: 14.0 V
 

·
Registered
Joined
·
13,695 Posts
I'm chasing an intermittent red light recently and I doubt Carl is going to give me my money back after at least 5 years of using the alternator he sold me :naughty:
Bloody thing is ALWAYS working as I pull into the garage so I haven't been able to test anything much yet...

I've checked all the wiring/connectors, removed and cleaned the two earth straps to the valve cover and the back of engine/gearbox casing, are there any more ?

Also installed a new starter solenoid ( thanks Joe!) as mine had suffered some melting and corrosion of the contacts - the fuse plastic was mostly melted :jsm:

The alternator appears to be working still even when the red light is on as the headlight still gets that little but brighter as the rpm increases from idle....

Is it likely to be anything other than the regulator before I pull the whole thing apart ? And has anyone ever managed to get the regulator repaired rather than replacing the whole alternator ?

Cheers
Rich
Probably not. But he would surely give you the mate's rate on another one if you need it.
 

·
Registered
Joined
·
313 Posts
today on the race track, the red light indicating the battery is low on voltage turned on. first, just for a few seconds, but then stayed on.

tested the charging voltage from the alternator and it is just zero.
apart from a broken alternator, could there be anything else wrong
with the electric system? any fuses, which may have gone?

fast help would be appreciated, as i have booked two
additional days on the track, and dont want to miss some
obvious flaw.

Edit: it is a F4 1078 312 RR
hello friend. apologize if my translation is not good and I do not speak English ....... while the same thing happened with my alternator and internal wiring had burned, the same also is used some brands of car, you change by car and fits perfect and works great ...... usated think you can get it at some car parts stock ...... ....... hope I can help if my answer is not clear I apologize I only speak Spanish

regards

Juan
 

·
Registered
Joined
·
1,260 Posts
Is in your situation the red-light always on? or it just
sometimes on/off during riding?

what is your voltage at the battery? maybe the alternator
just does not manage to have a high enough voltage for
the charging.

here are mine values as refereces:

battery voltage: 13.2 V
bike running without alternator: 12.5 V (red light on)
bike running with with new alternator: 14.0 V
It's sometimes on/off during riding. I'm yet to be able to get in in the garage, on the stand and still have the red light on to test the voltages. When I have tested the voltage without the light on they are as they should be.
 

·
Registered
Joined
·
1,260 Posts
hello friend. apologize if my translation is not good and I do not speak English ....... while the same thing happened with my alternator and internal wiring had burned, the same also is used some brands of car, you change by car and fits perfect and works great ...... usated think you can get it at some car parts stock ...... ....... hope I can help if my answer is not clear I apologize I only speak Spanish

regards

Juan

Juan,

¿Sabes qué coche utiliza el mismo alternador?

Cheers
Rich
 
1 - 20 of 28 Posts
Top