Charging system issues

[darrsi]

FWIW, the generator on the Fazer (and most bikes) is a magneto i.e. an alternator using permanent magnets. The term alternator just means ac generator, but is generally used to refer to those that use electromagnets rather than permanent ones to provide the magnetic field: they're bulkier but more efficient and are what cars use.


In theory, disconnecting the battery while the engine is running needn't cause a disaster. The regulator will continue to limit the peak voltage and, while the rectified ac will be very lumpy without a battery, the ignition should cope. However, it's not something I'd care to try and I agree with all the advice you've been given: as a diagnostic technique it stinks. If the regulation had failed volts could rise high enough to nuke the ignition unit and instruments.
The stator coils should measure 0.36 to 0.44 ohms so yes, yours sound about right (you'll probably be within spec if you subtract the measurement you get when shorting the multimeter leads together).


If the battery charger you used as a supply is a simple transformer and rectifier type, then the volts dipping to zero fifty or a hundred times a second would probably have starved the ignition and that is what stopped the engine in your test.
Provided there's decent continuity in the rest of the charging circuit then I'd agree the rectifier is probably to blame.
The easiest way to check is by substitution. I've never tried testing mine, my Yamaha manual doesn't give details, but if is a simple bridge rectifier and shunt regulator arrangement it should be easy to check. On the other hand, if it uses SCRs in the bridge to reduce the power the thing has to dissipate when the magneto is at full output I'll agree with Mr Haynes that it's too complicated to test with a multimeter.

Yeah......that's what i was gonna say 

[Andy FZS]

I find it's all so obvious once somone else has said it:D

[CRH]

FWIW, the generator on the Fazer (and most bikes) is a magneto i.e. an alternator using permanent magnets. The term alternator just means ac generator, but is generally used to refer to those that use electromagnets rather than permanent ones to provide the magnetic field: they're bulkier but more efficient and are what cars use.


In theory, disconnecting the battery while the engine is running needn't cause a disaster. The regulator will continue to limit the peak voltage and, while the rectified ac will be very lumpy without a battery, the ignition should cope. However, it's not something I'd care to try and I agree with all the advice you've been given: as a diagnostic technique it stinks. If the regulation had failed volts could rise high enough to nuke the ignition unit and instruments.
The stator coils should measure 0.36 to 0.44 ohms so yes, yours sound about right (you'll probably be within spec if you subtract the measurement you get when shorting the multimeter leads together).


If the battery charger you used as a supply is a simple transformer and rectifier type, then the volts dipping to zero fifty or a hundred times a second would probably have starved the ignition and that is what stopped the engine in your test.
Provided there's decent continuity in the rest of the charging circuit then I'd agree the rectifier is probably to blame.
The easiest way to check is by substitution. I've never tried testing mine, my Yamaha manual doesn't give details, but if is a simple bridge rectifier and shunt regulator arrangement it should be easy to check. On the other hand, if it uses SCRs in the bridge to reduce the power the thing has to dissipate when the magneto is at full output I'll agree with Mr Haynes that it's too complicated to test with a multimeter.

Yeah......that's what i was gonna say 

I find it's all so obvious once somone else has said it:D

....yes me too ...just wanted unfazed and fazerider to confirm what i realy knew already?...but like darrsi i dont like bragging ....that bloke haynes" knows fk all

[69oldskool]

Got any further on diagnosis & cure yet Boris?

[69oldskool]

How's this sound for testing the reg/rect?
Disconnect Red output lead,stick mulitmeter across output on 20v ish a/c voltage range~ run bike, but keep revs to a minimum, if ac voltage shows, rectifier part is swiss cheese~ chuck in nearest wheely bin.
If no a/c switch to dc voltage range~ & check it's in the ballpark of 12-15v.ish.
 
Stop engine &Reconnect output lead,then test regulator circuit as per factory manual with engine running.
 
Please DO NOT try 'til one of our more knowledgeable members has commented~ It's a plan, but it may be flawed

[BorisTheThird]

oh yes, sorry for the lack of response, got the new rectifier on which fixed it the charging

until... I noticed a sparks from the left just under the seat (the wires were still displaced and cover off from testing the stator).
3 or 4 of these wires had become bare from rubbing against the frame (i think) and no shorting to each other/earth. inc wires to the stator. 

so in better news, i think i may have found what killed my reg/rec, going to spend tomorrow pulling out the loop and replacing these wires   

[unfazed]

How's this sound for testing the reg/rect?
Disconnect Red output lead,stick mulitmeter across output on 20v ish a/c voltage range~ run bike, but keep revs to a minimum, if ac voltage shows, rectifier part is swiss cheese~ chuck in nearest wheely bin.
If no a/c switch to dc voltage range~ & check it's in the ballpark of 12-15v.ish.
 
Stop engine &Reconnect output lead,then test regulator circuit as per factory manual with engine running.
 
Please DO NOT try 'til one of our more knowledgeable members has commented~ It's a plan, but it may be flawed

You theory is good but flawed unfortunately, disconnecting the output lead could damage the regulator as the battery is a functional part of the charging circuit. There is a simpler way as mentioned in one of my previous posts and no disconnection of any wires required.
Set the meter to AC and with everything connected start the bike and check the voltage between the white wires of the alternator this is done 3 times accross the different wires to check all the alternator coils; (push the meter leads  (carefully) into the back of the plug) it should read around 18 to 20 volts AC. Revving the engine to 2000 revs will increase the AC voltage dramatically, if this is the case then the Alternator is working. If this does not happen the alternator is faulty. With the engine running at tick over, set the meter to DC and the voltage  measured across the battery should read over 12v and go up to an absolute maximum of 14.4 (may be a little bit less) when the engine is revved over 5000 revs. If the voltage does not increase and you have 18v AC + from the alternator then the regulator is faulty. If the voltage goes over 14.4 volts then the regulator is also faulty.
Glad to see Boris appears to have found the problem.

[Torque]

Stupid question, I've bought new rectifier, but where should I look on my FZS600?
Is it somewhere near horn? Or rear seat?

[unfazed]

Under the left hand fairing infill.