How to diagnose a fault in the charging system

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How to diagnose a fault in the charging system

Post by GeorgeMoroz » Wed Apr 12, 2017 9:17 pm

My bike is not charging the battery. I replaced my engine with a second hand race engine (conrod snapped) and he was running total loss so i put my genny on, and bot its not charging. I am not getting any voltage out of the genny but have continuity through all 3 pairs of pins.

Any help appreciated

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Re: How to diagnose a fault in the charging system

Post by banner001 » Thu Apr 13, 2017 9:13 am

you didnt read that guide did you?

first you need to charge your battery, unplug your generator and start your bike, now you need to measure the AC voltage across all 3 pairs of pins at about 4k rpm, the voltage should be reading ~45V AC for all 3 pins...this tells you that your alternator is outputting the correct voltage.

next you need to check your reg/rec, connect back your generator and check your voltage across the battery, it should be ~14.2V if its not then its your reg/rec or a wiring fault.

you can check the reg rec resistances (manual 15-15), and if you have 3 batteries lying about you can test the individual circuits (manual 15-16) - though ive never done this before.

your last option is to disconnect the reg/rec, make 3 dummy "yellow" wires going from your alternator to your reg rec (in any order), and then make 3 more "dummy" wires one going from the white pin to the 30A fuse (check that this fuse is good also), one going from the black yellow pin to the -ve terminal of your battery, and one going from your brown pin to the brown wire of the horn - this ensures that there are no wiring breaks (as long as your horn was previously good...), now fire up the bike and check your voltage at 2k rpm, if its still not 14.2V then its your reg/rec, if the bike now does have 14.2V then you know its a wiring break. you can also test the wiring using the coloured diagram i did, unplugging sections as necessary and testing for continuity down the various wires.
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Re: How to diagnose a fault in the charging system

Post by Kevh1070 » Sun Apr 30, 2017 3:07 pm

As a secondary note it's also worth testing your stator to ensure it's not grounded to -VE.

With bike ignition off disconnect stator core plug from loom, place multimeter probes 1 to any stator core pin & the other to any main engine casing. Set multimeter to lowest ohms meter range, if you get continuity then that's a problem !
Should read as open circuit, i.e. No continuity at all.

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