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[JoeDeloach]

Finally got around to doing some testing, after new cap and lead installed.

Engine off 12.35v
Engine off lights on 12.05v

Engine on lights off 13.95v
Engine on lights on 12.35v

The worrying thing is, is that with the engine on and headlight on the voltage drops, and visible drops quickly, goes from 13.95 to 12.35 in a few seconds. It's like as soon as the headlight is on, the bike is running on just the battery power and not charging, its like it disconnects from the alternator, hence why the speedo goes mental and the bike cuts out.

Not sure what my next step is, literally cannot see any bad connections anywhere, I'm thinking it could be a bad regulator or stator?

Thanks

[Haggis]

You can measure the stator windings for continuity and also measure their individual AC output.
CHECKING PROCEDURE
Set the multimeter in resistance mode.
Check the Resistance between wires
a. Yellow 1 to yellow 2 - 0.8 to 1.5 ohms
b. Yellow 2 to yellow 3 - 0.8 to 1.5 ohms
c. Yellow 3 to yellow 1 - 0.8 to 1.5 ohms

AC output from any pair of yellows should give you an AC voltage of varying levels depending on the revs, they should all read around the same and can read over 30volts. This is with the R/R unplugged from the alternator.

My bikes voltage with the engine running and lights on is always above 13v.
R/R are easy to test for correct function if you are competent with a decent multimeter.

[Daiwiskers]

12.35 is about 75% charged battery could be on it's last legs
Will battery hold 12.6 after charging? If not put battery on shopping list

Dai

[JoeDeloach]

Brand new battery, first thing I changed after buying the bike. Has to be the regulator/rectifier, I'm going to change that, if it doesn't work, bike will be partex'd for something else, getting frustrated with it, no issues with the bike with light off, but a mess when on??

[Daiwiskers]

Just because the battery is new doesn't mean its good.
I would take the battery off charge it then see if it holds voltage overnight if it drops to 12.35 after charging that is a duff battery

However it's odd that it drops to 12.35 with lights on motor running

Dai

[Daiwiskers]

Too late to edit I did try

All vehicles fitted with a ECU are incredibly sensitive to battery condition

Just because the newer Enfield's look old fashioned they are intact a modern vehicle

I hope that doesn't come over wrong I don't mean to sound condescending

Cheer's Dai

[JoeDeloach]

No worries, I appreciate any help, it's just incredibly frustrating when you can't see any obvious faults, and weird that when the headlight is on it becomes a bag of nails. I've bought a new R/R let's see if that helps, if not my only option is to px. Annoying because I loved the idea of an old British bike reinvented, I know its Indian made but honestly with the technology available today it should be better, not giving up just yet, a few more rounds before I throw the towel in.

[JoeDeloach]

Just tested again, battery good, ticks over no issue, side light on, voltage drops a touch but nothing to worry about. Flick the headlight on and the voltage drops immediately, in 2-4 seconds it's at 12.35v. I'm sure it's not the RR now, but I will change it for piece of mind but the bike runs well at 14v.

With the bike not running the voltage reads 12.35, turn the headlight on and it reads 12.05. Bike running 14v, headlight on 12.35 over 1 and a half of a voltage drop! Must be a short somewhere, does the headlight have a relay, maybe change that?

Cheers

[JoeDeloach]

OK, so after scratching my head over this more times than it's worth and a final test, isolating the earth (original loom) at the bulb and run a direct earth (brand new wire double isolated) from the battery to the bulb earth terminal I get exactly the same voltage drop down to 12.35v headlight on. So this must mean that the original loom does not have a bad earth, my conclusion is that there is nothing wrong with the bike, only that RE have used an alternator not powerful enough to charge efficiently at low revs, rev above 1500rpm and the thing starts to charge. I'm going to try a led bulb, hopefully the voltage drop won't be as dramatic and it runs more reliably. I appreciate all the advice, gonna have to live with it, no headlight, no problem.

[stinkwheel]

Just a thought. About half the shorts I've found on bikes over the years have been on instrument panel bulb holders. The bayonet type ones seem to be universally shite, they often rely on the casing of the holder earthing to the clock mounting. Try pulling the speedo backlights out, covering them in PVC tape and leaving them out floating free in the birds-nest while you do a road test.