anyone any advice on why battery keeps on going totally flat when running with lights on? totally dead ,but then if left for a while theres enough juice to turn bike over and start it?
can run bike with no lights ok.done this with 2 batterys.
tested reg/rec at 5000rpm and getting about 15-16v but when lights on voltage drops below 12v.
also tested yellow wires out of alternator getting 450ohms which haynes suggests is right.

really stumped here any help suggestions please???

Your altenator and reg/rec sound buggard.

your not supposed to have 450ohms from the altenator wires.

Between the yellow wires your supposed to have 0.1 - 1ohm.

15-16v is too high too. It's supposed to be 14.1

sorry meant pulse coil resistance 450ohms. think its white/blue to blue and green/white to green.

should the voltage jump to 14.4v at 5000rpm or slowly increase?

the charge rate at the battery should be between 13.5-15volts at 5000rpm.

this is without the lights on.

i would suspect the alternator to be on it's way out.

best bet is to test the voltage output of the alternator and go from there.



william

right think ive found the culprit.reg/rec.
got a new reg/rec with fins a couple of years ago and think its goosed when it gets hot.
put old one on (original working one) and getting 14.4v at 5000rpm.everything else tests out ok.

will see in next few days how it goes.thanks for help