ClevelandView007
Parking Attendant
Posts: 4
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posted July 30, 2012 07:52 AM
Alternator output voltage 79v @ 4000rpm on all 3 outputs.
Alternator output voltage 79v @ 4000rpm on all 3 outputs.
Manual says it should be 85~120v @ 4000rpm.
What could cause this?
Battery reads 13.6v at 4000 rpm, lights on etc
Manual says 14.2v~15.2, but is this with lights etc on?
ZX12R
PCR3
LCD
Shifter
Akro
BMC
2005 model
Going to test resistance across stator coils, and to earth again tonight.
Resistance across coils reads 0.001 ohm with meter on 2ohm range.. but going to double check.
Manual says it should be 0.3~0.5 ohms with meter on 1 ohm range.
   
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ClevelandView007
Parking Attendant
Posts: 4
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posted July 30, 2012 12:24 PM
Quick update. Battery in meter was dying so re-checked everything tonight.
At 4000rpm battery terminal voltage is 13.6v
Manual says 14.2~15.2
Resistance across stator coils is 0.6 ohms on all 3 (set at 200 ohm range on meter)
Manual says 0.3~0.5 ohms
Resistance to ground is infinity (1) (set at highest range on meter)
Manual says infinity
Output from alternator is 78v at 4000 rpm on each stator coil
Manual says 85~120v at 4000rpm
The symptoms are, brand new expensive Yuasa battery 2 years ago (£100!) and is on Optimate when bike isn't used. The bike has let me down on 3 occasions recently while out, ie it won't start, and it appears to be a flat battery. Just put a new battery on and it starts fine...... at the moment, but worried something is at fault...
What should I check next or is the rotor losing its magnetism?
Any other ideas anyone?
Or would you just live with it?
TIA.
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biggmoinc
Zone Head
Posts: 747
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posted July 30, 2012 05:08 PM
Hey cleveland, we both have some issues, lol, U said the resistance to ground is infinity, and coils is .6 ohms, the manual says that if there is more resistance than shown in the table, or a reading of infinity for any two wires that the stator has an open wire and must be replaced, i may have actually found my answer now cause it says that if the resistance is much less means the stator is shorted and must be replaced, looks like we both going to need a stator, lol, just weird why mine output showed 116@4k and the resistance was too low
____________
07 ZX14 bmc filter, muzzy m14, 16/44,66",auto shift, 6'3, 204lbs/1.54/3.99/6.03@120/7.8/9.32@147
biggmo@aol.com
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ClevelandView007
Parking Attendant
Posts: 4
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posted July 30, 2012 10:00 PM
Hi Biggmoinc, it's a bugger isn't it.
Just re-read the manual. It says "it there is more resistance than shown in the table (this is across the coils, not to earth btw), for any two leads, the stator has an open lead and must be replaced. Much less than this resistance means the stator is shorted, and must be replaced."
In the next paragraph in the manual it says "Using the highest range on the hand tester measure the resistance between each of the yellow leads AND CHASSIS GROUND. Any hand tester reading less than infinity (1) indicates a short, necessitating stator replacement"
... tha manual goes on to say "if the stator coils have normal resistance, but the voltage check showed the alternator to be defective; then the rotor magnets have probably weakened, and the ROTOR must be replaced"
At the moment I am thinking going the rotor route. No point in buying a new stator of the magnets on the rotor are buggered I guess.
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tuusinii
Pro
Posts: 1031
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posted July 31, 2012 02:00 AM
What is You're voltage at battery when idling? It should be close to 14V. Batterys can die in two Years. If You're measuring 0.6 ohms at normal multimeter that is close enough because it's not made to measure very small resistances. You can check that by just measuring the resistance of the multimeter leads. Also the AC measurement isn't exactly accurate if the multimeter isn't true RMS meter and can give couple volts differences. Normally that is 0.1 to 0.3 so You can remove that from Your measurement which puts You in the middle of the book value. Also that 13.6 should be close enough. What is Your battery voltage if You have charged the old battery and lett it sit for 24 hours? should be close to 12.7 if it's full. One thing where I've had problems is the cable "bolt" trough the battery housing. That was loose on my bike one time and also a little rusted. When I cleaned it and tightened it started much better.
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ClevelandView007
Parking Attendant
Posts: 4
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posted July 31, 2012 03:57 AM
Thanks for the post there Tuusinii.
I have stripped the whole battery box down and cleaned all the connectors so they weren't that bad tbh.
My meter is only a cheapie so yes, I would tend to agree with you about the readings I am getting, hopefully it was just a duff battery I had on previously.
Yes, the battery voltage at high tickover (1250 or thereabouts) does peak at about 14v and drops slightly at the 4000rpm speficied in the manual.
It says to meter the resistance on 1 ohm range on meter, mine only goes down to 200 ohms.
So maybe I am worrying unduly.
Thanks for your input, appreciated.
Hope you get yours sorted too Biggmoinc. 
Cheers
Steve
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tuusinii
Pro
Posts: 1031
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posted July 31, 2012 04:39 AM
One indication about the battery is also the voltage when You're cranking - it shouldn't drop below 10 volts or so. Othervice there is something either in the battery or in the starter. Let's hope its keeps that way. Have You by the way checked that the connector to stator are good and no oil?
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