battery light on

[rossi46]

Hi gents I just returned from a Euro trip, will post pics and write up soon, I encountered a few issues the first of which is that for the last few days the battery light will come on when running, I checked what I could on the road, battery and ground wires, reg. is cool to touch and puts out 13.70v @3000rpm,I travelled 300mls yesterday 50% of the time the light was on, we stopped regularly and checked the battery voltage and it was at about 13v so I assumed it was ok.Arrived home safely took some readings today key off 13.06, key on 12.79, can anyone give shed some light on this? thanks

[gstallons]

Check your battery voltage tomorrow before you start the bike.... it should be around 12.65 v .

[fotoguzzi]

do you have a supplemental ground from the reg to motor? you should! the ground is passed thru a captured bolt, not a good design.. probably not your problem but shouldn't the run voltage be 14.1 or so not 13/7?

[docc]

Also remove and inspect the 30 amp regulator fuse looking for signs of high heat, melting, or charring.

 

Be certain the battery terminals are well tight.

 

Finally, remove the alternator cover and inspect the two yellow wires leading from the stator coils for broken strands.

[rossi46]

thanks guys-battery @13v this morning, I have a additional ground wire-will check the the stator wires on the weekend-could my reg. be failing? I have a spare so I might change this too

[rossi46]

quick update-replaced the reg. and getting 14.2v @3000rpm, had a few rides and all seems good! thanks

[Kiwi_Roy]

rossi46,

             If you have a multimeter with the diode test function (--->|---) would you please test your old regulator

Red lead of the meter to each yellow of the regulator black meter lead on the double red.

Both yellows should read between 0.4 and 0.6 Volts.

 

Thanks

 

Roy

[rossi46]

sorry Roy didn't think, already recycled!

[st. augustine]

my gen light is also acting up.  sometimes it stays on, sometime off, sometimes just barely lit....most times I can turn the key/switch on off and the gen light goes off.  Ride a few more days and it starts all over again.  Can Roy expand on where he was going with that response?

 

Cheers,

 

James

[docc]

James, Roy has often said that if cycling the ignition switch affects your bike's function, it should be disassembled, cleaned, and inspected for broken connections. Easy job worth the effort!

 

Also, be sure you have tight connections to a high quality relay in position #2.

[Kiwi_Roy]

The battery Voltage is effected by the headlight relay and in some cases by the start relay Voltage drop.

It's also effected by the bike wiring and lamp selection, if you have headlight relays powered directly from the battery the drop will be less, larger headlight bulb it will be more.

 

You can measure the Voltage drop from battery Positive to the black wire at the relay with the key on.

Measure it then cycle the relays, you might be surprised how much it changes especially if the relays haven't been touched in quite a while.

[docc]

Measure it then cycle the relays, you might be surprised how much it changes especially if the relays haven't been touched in quite a while.

The open relay contacts get corroded? Not unlikely on the salty Atlantic coast . . .