Hitchcocks Forum

Hi all, my bullet dumped me at the roadside on saturday night (in a dark forest at way past midnight). The electrics were playing up. The engine would run but the lights were basically giving up (indicators barely glowing and back light ended up giving up). Eventually the bike would not even run. I abandoned it and on my return the next day the bike fired up and the electrics were back to normal (my thinking was the run I had been on had put some juice back into the battery). As the battery was probably way past its best (it did show 11.4 volts though) I fitted a new one on tuesday. Now when running the ammeter does not go into the green which indicates to me there is no charge going back into the battery. Now my limited knowledge of electrics thought this may be the reg/rec but the needle instead of being way over to the right is just sitting dead centre. It does swing to the left when the electrics are put on but just by a small amount. I guess my question is should I be concerned the needle is sitting pretty much dead centre when the bike is in use? Do not me fooled by the fact I own a voltmeter. I have no idea what I am doing. Nearly forgot, its a 350 iron barrel from 2007. Thanks in advance.

Sounds like the charging circuit isn’t working. Flat batteries will recover a little if left for a while. Sounds like that is how the bike started the next day.

Sounds like your ammeter is fine, Aethelric is probably on the money here. Might be time for a new reg/rectifier? The alternator itself is probably OK but you could whip the primary cover off to check for signs of damage or burning out, and that the wires from the alternator haven't come adrift or been chewed by the primary chain. Also check the wires from the reg/rectifier to the ammeter.



A.

If you have a separate rectifier and regulator, then you can simply disconnect the regulator and if everything else is OK you should get charge. Don’t run the engine too long though as you can overcharge the battery.

A 2007 350 should have an AC/DC system. As such, the lights AND the engine failing suggests to me that the alternator is goosed and you're running on whatever charge is left in a failing battery. The lighting should be a totally separate system to the battery charging.



You have that voltmeter, now is the time to use it. Set it to measure volts DC, you should get a higher than resting voltage across the battery terminals when the engine is running and it should increase with revs.



If it doesn't, you have a charging problem. You can also test the alternator output. Set that voltmeter to measure volts AC. Disconnect the reg/rec and measure voltage between the two violet wires with the engine running. It should read over 30V AC, again increasing with revs. If it doesn't, your alternator may well be toast.



If the alternator is ok, there could be something more odd like a short in the ignition switch or similar but checking the battery for charging and checking the alternator output is a good starting point.

Do the easy things first
With the engine running at fast tickover connect your voltmeter to the battery. Then come back and tell us what the reading is.
Should be around 14 -15 volts

I should add that a dead reg/rec can be the cause of a burned out alternator so if you land up replacing the alternator, check the voltage output across the battery isn't excessive as soon as it's fitted and replace the reg/rec if it's too high.

Thanks gents. I took the advice of easy things first and indeed with a fast tickover there is no change in voltage. Just sits at 12.4volts. So I take it from this I need to investigate the alternator and the reg/rec in that order. As suggested by stinkwheel i will next test the alternator voltage by putting the voltmeter to AC and judging by a youtube vid putting the two ends of the voltmeter into the violet wires and I should get a current in the 30 volt mark. Will report back.

Stinkwheel correctly identifies the two wires from the alternator (on post 1999 bikes) which feed the reg/rectifier as being both purple, but there are some pattern alternator stators around which have red and black wires instead of purple.



A.

The wires going into the reg/rec connector block SHOULD still be violet though.