Electrical failure - battery, regulator.

Had myself a typical curvy breakdown this morning.

I'd ridden 14 or so miles from home into work perfectly fine, I pulled in the clutch to gear down whilst rolling upto some lights and ZAP, all the electrics seemed to be working but the bike wouldnt fire. Hit the starter button and nothing...

So thought the usual (fuse, dodgey earth etc). Got the recovery home and have now stripped seat and side pannels etc. Im shocked to see all fuses are fine and all circuits seem to be working well. In the silence of the workshop I can hear the clicking of the circuit but no fire or turn in the engine. After trying/playing with indy's full beam to try and see some fade in the electric power eventually I did notice the instrument panel start to dull.

Which sounds perfect for a dead battery, only thing been that I'd already travelled the 14miles :S

So... my question really should be if the reg/rec had conked out but the battery still had some charge from its prevous use would the bike start; work fine until the battery was empty?
once its charge dropped past a certian level would the motor die?
Would it then fail to do a rolling start?
Slowly as more charge is lost would other stuff dim/die off?

ANd again, all ideas and comments are welcome.

[Biker Biggles]

Unless you can locate a loose connection or other obvious cause you will get nowhere until you get a multimeter and find out what the problem is.It may be a charging system fault or a duff battery or both or something else,but you need to find it.

[fastdruid]

Dodgy earth?

Bear in mind that on the SV the earth to everything is is *not* through the frame[1] so you *will* have lights, instruments etc but no spark and no starter.

Very typical this time of year due to salt, remove the bolt from the rear of the engine, clean it up with some emery paper and use copperslip on the bolt.

Druid

[1] Some bikes it is[2] so a dodgy earth is recognised by total electrical failure.
[2] For example my NC35 track bike the earth for the loom is attached on to the frame by the front coil, the earth from the battery is *only* directly to the frame.

Ok, Just charged the batt for an hour or so and re-connected everything and its running again...

Now I've got to determine why it cut out in the first place.

So some more info - Multimeter readings:
(all readings are taken with the multimeter red to +ive battery terminal, -ive to frame)
Ignition Off - 12.17V
Ignition on Bike not running - 11.62V
Bike Running at idle (1500rpm) - 11.91V
Bike Running at 3000rpm - 12.02V
Bike Running at 6000rpm - 12.01V

Does this mean the reg/rec is kaput?

I'll do what you say anyway druid, nice to know little tips like that.

Not sure about Curvy..but pointy charges (bike running) at between 14 and 15.5v

[Biker Biggles]

Search for Sid Squid post here on checking the charging system.It explains exactly what to do including how to check alternator output.I suggest you do that first.

spoke to the northern sv guru got a few things to do which he suggested but defo appears to be reg/rec as voltage is all but equal at the reg/rec as it is at the battery.

Yeah...you've got no battery charging going on there. A 12v battery isn't really 12v - it's a 12.7v cell. When you say after a few hours of charging, was this on an optimate type device? If so, was it saying that the battery is full? If so, the battery's dead, too - a fully working, freshly charged battery should be reading between 12.6 and 12.9v.

Ideally with the bike idling you want somewhere between 12.4v and 14v going to the battery, and when it's above 5krpm it should be running at 13.5-14.5v or so.

If you can get the bike running and get to the reg/rec, is it warm? The reg/rec changes electrical energy to heat to stop the battery from being overvolted, not undervolted. If it's hot, then it's shot - if it's cold, it'll probably be something else in the charging system as there's not enough voltage for it to regulate.

[yorkie_chris]

Your next check is the alternator.

Set your meter to 0-100ACV, check the voltage between those 3 yellow wires while running. You should have 60v or so on each pair