bike charges fine with lights off, when I put lights on it drops

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fstarocka
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Joined: Wed May 04, 2016 6:33 am

bike charges fine with lights off, when I put lights on it drops

Post by fstarocka » Wed Oct 12, 2016 5:20 pm

New battery that seems to hold its charge well, had it charged at a shop today.. measured the charging from idle (about 13.3v) - revving to about 5k gets it to 13.9v.. prob a little more if i had to rev higher.

Now when i pop the lights on it drops to about 12.85 almost instantly.. the batter v was at 13.35 without motor running, so thats even lower than the battery.

What does that mean? maybe the generator is going? are voltage checks enough to test the gen? i did tests on the 3 yellow wires but cant recall what they were doing but if i remember correctly they seemed all very close.

The lights were bloody cut off by the previous owner - so i cant say i re connected them correctly - however I did follow the wiring diagram and basically joined the same colors to each other.. i think it was red/yellow and red/white (high beam?).. anyway - all the lights worked correctly, high beam made the blue light come on, both lights were on high - low as well..

any ideas?

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banner001
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My Bike: ZXR400 L4
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Re: bike charges fine with lights off, when I put lights on it drops

Post by banner001 » Thu Oct 13, 2016 9:30 am

generator, or your reg/rec, or your wiring down there has fried.

check the wiring first for faults, then change the reg rec, if you have a multimeter set to measure AC you can measure the output of the alternator, should be 45V AC across all 3 pairs of contacts coming from the alternator at 4k rpm.
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003

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