MOT with a dead battery

[RVF007]

I got up early and shot off to work for a few hours on the NC35...the bike started perfectly, left work at 11:00 because I had my MOT booked for 12:30. Stopped at home for a quick bite to eat and off too the bike shop...bike started as normal, perfectly. Got to the bike shop, parked up and went inside and handed over my key's so the bloke can take the bike into there workshop. A minute later the bloke is back and wants to know how I got the bike there cos its dead?
The bike was as dead as road-kill. Arrggghhhh bitch! I went over and tried it and all it did was about half a turn and it stops....
So not just did I get my MOT but also a new battery...

It just shows how quick a battery can pack up and without any warning.

[viper_biker]

Was the bike in gear when it was tried to be started up? Or was the kill switch on? Might sound silly, but the simplest of things can take forever to find.

[RVF007]

no we did a couple tests, took the terminals off and tested the battery...12V. Put the terminals back on, switch the ignition on and gave it a turn over... the reading dropped down to like 4V. We also checked the charge on the terminals and it was around 12V with the bike running @ 4000rpm.
Hope thats all it was and not an electrical problem.

[wullvfr]

if the charge rate does not go up at all then it sounds like a dud reg/rec.

the voltage should actually drop a little bit at a time.

if the voltage does not drop but does nothing much then test the output of the alternator,as this may be faulty.



william

[RVF007]

when the bike was at idle and you give it some throttle the reading on the terminals would go up to about 12v + and when letting the throttle off it will drop again. I did notice that the dash/neutral lights was not bright at all, very dim and with a bit of throttle they brighten right up.

[wullvfr]

i would suspect the alternator then.

to test the output of the alternator:

remove the block connector by your right knee,it is the one with three yellow wires.you test the female side of the connector,this is the connector that comes from the alternator.

set the multimeter to ac volts minimum range of 100.with the bike @5000rpm take a reading between two of the three yellow wires,then move one probe onto another yellow wire and so on until you have taken three seperate readings.

all readings should be at least 50 volts and all the same.

from what you have told me and if the alternator is faulty then i think your readings will be as low as 30volts,maybe even lower.


william