Charging probs

[Tim H]

Hi all, I've got a k6750 and a 400/4 and neither will charge. The 750 has been completely rewired and had replacement regulator and rectifier and new battery but still cant get it to charge, I have tested all the components and they all seem ok.  The 400 has replacement regulator off a 500/4 but this will not charge either and I am starting to pull my hair out!!!!!!
Was told a cb 250 reg/rec unit would work but does not have enough wires on it 3 yellow,red,black and green but no white for the alternator. Any help would be greatfully received.
Cheers Tim

[jimshea]

Tim,
SteveD is the electrical wizard, I am sure he will see this post and reply. Silly question, but are you sure the charger is OK??
Where are you located?
Cheers,
JIm.

[jimshea]

Tim,
SteveD is the electrical wizard, I am sure he will see this post and reply. Silly question, but are you sure the charger is OK??
Where are you located?
Cheers,
JIm.

[Tim H]

Hi Jim,
 Both the batteries charge on my charger and show 12v on meter but stay at 12v when the bikes are running. The manual suggests about 14v at 3000rpm but I still only get 12v. Thought it was a bit odd that both were doing it but my mate checked it as well.
I'm in Kent by the way.
Cheers Tim

[SteveD CB500K0]

I wouldn't call myself a wizard but these charging systems are fairly basic and therefore simple to faultfind.  I fixed Jim's which is why he thinks I'm a wizard (just an electronics engineer by profession)
All the SOHC Fours (except the 650) use the same system with simple individual components.
If your battery is sitting at 12V with the engine running, something must be happening as it would run down the voltage very quickly if not charging at all.
The battery should sit at 12.5 (ish) with the ignition off which then drops to 11.5 (ish) with the ignition on.  This is because these bikes use energised field coils which draw current even when nothing else is happening.
The regulator measures the battery voltage and switches the field coils on or off depending upon whether the voltage is above or below the trigger point. This trigger point can be adjusted on the regulator (but don't do this yet...)

The O/P of the alternator is three phase (yellow wires) 24ish volts and is rectified down to about 20V DC by the rectifier (although you should never see 20V if the battery is connected and in reasonable condition).

So.
Check AC voltage output from the alternator.
Check DC output from the rectifier
Check the field coil output from the regulator
Can't remember the colours as I'm at work at the moment.

Post back.

Where in Kent?

Steve

Post edited by: SteveD CB500F, at: 2006/10/31 11:48

[verduijn]

I have a CB750 F1 with charging problems.
I disconnect the alternator plug, and start the engine.
If i measure the current I see nothing.
Between which colours do I have to measure?

I hope you can help me,

Regards
Huib Verduijn