My bike is running fine. Not had any problems with it.

Just trying to pre-empt any.

When not being ridden the bike is hooked up to a trickle charger - so the battery is always fully charged. It is also fine left overnight after a long run - I've been going away for the weekend on it - and it fires up no worries at all in the morning.

Checking the voltages (across the battery) this morning:
- bike switched off - 12.52V
- bike on lights but no engine - 12.4V
- bike on at idle - 14.2V
- bike revved above 5000rpm - 13.5V

It is the last reading that made me go

Any comments on this - or am I just being paranoid with my bayybeeeee...

I was just doing mine actually - I get a 13.12 off, 13.10 when on, 14.4 when idling and 14.2 when approx 5k revs.

My wiring is getting a bit charred.... I am finding that I have the grump with the bike in general.

Yours will be reet lad..

I've noticed that my voltmeter drops a tenth or two when using higher revs. I always figure that higher revs means more sparks means more energy used.... 13.5 at 5K is not stellar, but it is just within spec. If anything, the 14.2V at idle surprises me, most people struggle to beat or even reach the lights on but engine off figure!

Loads of info here about making improvements, if your reg/rec and stator are healthy, all the gains and in the wiring.

manicguitarist wrote:My bike is running fine. Not had any problems with it.

Just trying to pre-empt any.

When not being ridden the bike is hooked up to a trickle charger - so the battery is always fully charged. It is also fine left overnight after a long run - I've been going away for the weekend on it - and it fires up no worries at all in the morning.

Checking the voltages (across the battery) this morning:
- bike switched off - 12.52V
- bike on lights but no engine - 12.4V
- bike on at idle - 14.2V
- bike revved above 5000rpm - 13.5V

It is the last reading that made me go

Any comments on this - or am I just being paranoid with my bayybeeeee...

Sounds ok to me :)

IMHO, if 13.5 volts is the max reading at 5000 rpm then the battery is not going to get a full charge. More than 14 volts is required and this only appears to happen at low rpm, which is unlikely to occur at cruise speed going by the readings shown.

The "long ride will charge the battery" philosophy will not work if the charging voltage does not reach the required minimum.

If that is the resting charge for the battery when not connected to the bike, 12.52v is low for a fully charged battery and suggests the battery is old. Yuasa's Technical Manual says:

Open circuit voltage for a fully, 100% charged AGM battery is 12.8 to 13.0 volts. AGM batteries that are
75% to 100% charged will measure 12.5 to 12.8 volts

Ciao,

Just went to the bike to check charge with battery disconnected (ah the joys of "working" from home) - 13.36v not connected.

i'd expect 14 to 14.5V when revved above 5000

If you want to know the true output of the rect/reg why not measure the output voltage at the red and green wire terminals at the rect/reg.

Another factor to consider is the thermal sensitivity of the rect/reg control circuit. One of the by-products of good thermal flow out of the rect/reg, other than reliability, is thermal stability of the reg control circuitry.