[Dave1]

Hi guys,

My bike has developed a weird problem. When I switch the headlight, indicators, or use the horn, it cuts the bike out, with the engine at ideal, and sometimes low revs when being ridden. Also my Ammeter appears to have stopped working.

I'm thinking it is either a bad earth? Which I already looked at the main earth from the battery negative terminal to the frame is fine.
The other thing I think could be causing this is the alternator is on its way out and very close to going kaput?
Or could it be a very bad short?

Dave

[Adrian II]

I had this with a Honda 125 once, turned out to be a duff rectifier, though Honda 125s then at least didn't have AC direct headlights, which should not affect anything else in the rest of your electrics.

Try running with the the half of the alternator that charges the DC side disconnected, possibly the reg/rectifier too, but with a fully-charged battery. If I remember correctly your bike is 2003/4, plenty of time for the OEM reg/rectifier to go t*ts-up since then.

I'm re-wiring an Electra-X soon, bring it round if you need to!

A.

[Dave1]

Cheers for the help Adrian, when I get sometime I will pop over. I will give the bike a test ride around here, to see if the bike can be ridden safely.

Will have to figure out which is the DC side of the alternator. My headlights have always been on the dim side, which of course run off the AC side of the alternator. The lights are dim To the point where the MOT examiner always scratches his head at them each year..If you know what I mean.

[Adrian II]

The alternator wires which go the the reg/rectifier side of the electrics will either be purple and purple (OEM) or possibly red and black (some pattern stators), the yellow and amber wires are for the AC headlight.

A.

[Dave1]

Cheers, Adrian, I know mine has the purple purple wires, as it still the OEM alternator. Rode the bike this morning, there is no way I could ride it over to you. I just tried to restart the bike after test riding it, and it wouldn't start. Hope it will later! Otherwise I'm not going to be able to test the electrics. Which might mean a total rewire, if I can't see a problem. Like a short or what not..

[Adrian II]

Oh well, keep trying one thing at a time, process of elimination. As regards the ammeter, you can bypass it to see if it's the problem. I would also run a wire directly from the positive terminal in the battery to the ammeter to see if it's a loom issue.

You can get generic single phase reg/rectifiers very cheap now if that's where the problem lies.

https://www.ebay.co.uk/itm/Universal-12V-4-Wire-Full-Wave-Motorcycle-Regulator-Rectifier-Bike-Quad-Scooter/253804522169

A.

[Dave1]

Is that eBay single phase reg rec a direct replacement for the two separate units on the RE? Like I'd just plug it into the existing connection on the frame ? The plug looks correct, I wouldn't need to change the wiring ?

[axman88]

Are you sure the battery is good?  What you describe sounds like it might be a cell gone bad or high resistance.  If you get a voltmeter on the system that might shed some light on things.

Better check the pin-out on the replacement.  I need a new rectifier myself for my 1999, and also have the split unit.  Just one diode went out, which effectively cuts off half the power.

I was thinking of switching to a LED headlight, which uses a fraction of the power.  This would place much less demand on the headlight winding, and might overtax the zener shunt regulator.  I was thinking of rewiring my alternator to go three phase, getting a 3 phase rectifier/regulator like the UCE bikes, and running the headlight off the battery.  What do you guys think of that idea?

[Dave1]

Hi Axeman, no I haven't checked the battery. I will put a multimeter on it tomorrow, to see what voltage it currently holds. If that's low then I will see what my smart charger says about the condition of the battery. If the battery can be charged, and I can get it going to do all the other electrical tests, I will be happy!

Never heard of somebody reworking an Iron Barrel Bullet to Three phase only, usually it is the other way round, some people rewire there bikes the single phase only ( DC ).

Adrian, how do I bypass the Ammeter?   

[Adrian II]

To bypass the ammeter, just disconnect the two ring terminals and bolt them together with a 2BA/5mm screw and nut, remember to insulate it well. I'm trying to think if that ebay reg/rectifier is the same one that Rex's Speed Shop sells in the UK as a direct replacement for the Indian Bullet items. Looks like it uses 2.8mm terminals.

https://www.rexs-speedshop.com/product/royal-enfield-bullet-regulator-rectifier-1995-on/

Indian Bullets certainly have been upgraded with 3 phase alternators, either Lucas or Sparx, someone on this forum posted their wiring diagram quite a long time ago!

For what it's worth the Electra-X/AVL Classics also have three phase alternators.

A.

[Dave1]

Well I managed to do some tests today. The battery with engine off was holding 10.3 volts. Started the bike and at its current idle it was 11.5-12 volts. Tweaked the engine so that the idle was 12.5 volts being put into the battery. So slightly high idle. When I revved the engine up the volts going to the battery would not exceed 15.5-15.7 volts. Is this normal?

What's the cut off point for the reg-rectifier?

[Dave1]

Hi guys turned out that my battery is dead even though the multimeter suggested otherwise. Had the battery tested by a pro with a decent battery tester, my smart charger also came up with dead battery. So in the future I will just check batteries from now on with my smart charger. I have ordered the cheap replacement regulator and rectifier, as the reading from the standard ones where a bit high.

[axman88]

10.3 V sounds right for a dis-charged battery that has one bad cell.

15.5 volts is pretty high.  The alternator was trying really hard to charge up your deceased battery.

Glad you got it sorted out Dave.  There's nothing better than a volt meter and a little knowledge for solving electrical faults.

[Dave1]

Sorry don't think I was clear in my last post. The battery was dead. 10.3 volts is usually ok, on a healthy battery. The battery was basically acting as a large capacitor. The multimeter did nothing in aiding the diagnosis of the dead battery. The professional battery tester, and my smart charger. Diagnosed the dead battery.

The fact that my regulator rectifier allowed over 14 volts upto 15.7 volts is a sure sign that the regulator rectifier needs replacement.

Really 15.7 volts isn't a sign at all that the alternator was trying hard. A OEM alternator should be able to achieve 30-50 volts if healthy. The fact that I was testing the voltage after the regulator rectifier at the battery, means it would be a very unsatisfactory insight into alternator health.

I will be disconnecting the violet wires after the installation of the new battery and cheap Japanese regulator rectifier. That's the proper way of testing the alternator, as Adrian pointed out earlier.

[axman88]

I have to disagree on a couple of points.

First, I'm pretty sure that RE alternator has no field winding.  My understanding is that the shunt type regulator just dumps unwanted power to ground, working downward from max. output which would be the 15+ volts you measured.  You will see higher AC voltage, ( like 30V) on the alternator side of the rectifier, but I don't think that's what you were measuring.

Second, where I come from, on a 12V system, with no load, 1.8V per cell is fully discharged, and getting worse by the hour (sulfating), and 2.1V per cell is fully charged.  Your measured 10.3V is deader than the 10.8 volts that would be a dead 6 cells, and was most likely a reading of 5 good cells almost fully charged at 2.06V / cell.  10.3 is never good for a 12V system, but would be fine if you had a 10V system.

So your voltmeter was telling you the whole story if you knew what to look for.  There's a lot of good information on Lead Acid technology here:  https://batteryuniversity.com/learn/article/lead_based_batteries