ETZ251 charging light

[Blurredman]

Hi guys,


My charge light is sometimes very dimmly coming on when riding my 251. It's extremely dim to see it at all in the daylight, but I have a voltage output gauge that I've had strapped to the handlebar since 2016, so I can see when specifically the battery sometimes doesn't receive any charge.


So far I have replaced the brushes and brush holder. But I have also tried a different rotor too actually. The items themselves all look in fair condition and with good wear still remaining.

My next point to look at, although I have a feeling I have already tested it out breifly, is to change the voltage regulator. Currently I have got a solid state one which was on the bike when I bought it (has now covered almost 20k miles in my ownership, I have no idea how long the item has been on the bike before that) - though I have plenty of mechanical ones to try out.


However, part of me thinks it is not the voltage regulator, because sometimes the charging is intermittent, both starting/stopping whilst riding. And sometimes, it is a little gamble as to whether the red charge light will be illuminated when I turn on the ignition, sometimes it is not. So I don't think the voltage regulator itself would be required in that instance? Only the brush connection to the slip rings?

Personally I think it could also just be the green and blue cable between stator and regulator (DF) could be defective in some way? However one of the last time I noticed this issue, removing the brush cage and putting it back seemed to fix the problem. Though I suppose this could be coincidental...?


Curious as to whether anybody has any pointers please?

[Puffs]

Removed

[DAVID THOMPSON]

an old timer said once that The indicator bulb in some systems ISpart of the system
his fix was a new oem bulb in a good cleam lamp socket with a goog tined wire to the point bring measured
he ran h[size=150]4[/size] 6v bulbs in his 6v bmw bikes had a relay on thehandle bar switch to lower current i h/l handle bar sw

[Blurredman]

Aha. So in my attempt to replace the regulator with one I know works, I had to move out of the way the electronic ignition 'box' that is mounted via the the main earth point adjacent to the terminal box on the air box. When I loosened the electronic ignition box, an earth wire came out despite not yet removing the bolt. The earth wire that came out was the one that leads to the regulator! Picture attached is how i've always had the electronic ignition box mounted utilising the main earth bolt as a way of keeping the EI box secure.

So, it becomes apparent that I hadn't put the hold down bolt through wire terminal 'eye' and it must have been just squashed down there amongst the other earth wires, sometimes making a connection, and sometimes not.

As it is- I still replaced the regulator but i'll use the bike and keep a track of what happens. If all goes well, I'll reconnect the old regulator and that will confirm/deny the fault was with regulator or indeed as it seems merely this earth wire...

[Puffs]

Good! Let's hope its just the earth cable.

[Blurredman]

Ah.

So this has seemingly not been resolved by a different regulator and fixing the earth wire properly... The charge light came on briefly today whilst doing about 50mph (not that speed has necessarily ever been a connecting factor- just thought i'd point it out), for approximately 10-20 seconds. But this time had a bright red charge light as opposed to a dim one (maybe because it is dark, or indeed maybe because the earth is being properly utilised(?)). But then the light went out and I could see in my voltage display that it was charging and it continued to do so without interruption for the rest of the journey... Definitely looks like it will be a problematic one to fix, perhaps.

But I think the next thing to check I suppose is the blue/green wire from generator to fuse box, then fuse box to regulator, including the connection at the fuse box.. But also, it might be worth replacing the rectifier itself too with one I know that works. Perhaps there are dry joints on the rectifier unit...obviously I can fix these, but using a known replacement would give me the quick fix. I suppose I could start experimenting by removing wires from the generator end whilst the bike is running and see what effect this has on the charge light (perhaps) as that might give me a little indication on where I need to focus my input.

[Puffs]

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[Blurredman]

I realise (and possibly this is quite a pointless exercise considering the state of the forum) that I never updated this thread.
The problem I fixed about March/April 2014.

I didn't use the bike much before that time but in those small miles before it was not being used for a year previous to fixing the issue, the problem was getting worse and worse and random in conditions. The problem was actually simple to resolve - it was just a corroded terminal (previously the original terminal had been replaced with an aftermarket crimped item a long long time ago by me I think in 2016, and you know I had these issues come and go for several years so it might have been all my fault originally anyway). The particular wire I am talking about is the sense/charge signal wire (DF) at the alternator side.

Infact, it was very easy to simply pull the terminal away from the wire with minimal force as the two strands of remaining green/black copper just snapped. The crimp was not good, and the exposed copper wire was oxidised. I stripped the wire to shiny core and a new terminal soldered on (I know some don't like soldering, but I do as of the last few years). Which was the next easy logical thing to check as per my previous post.

Before messing with the thing I decided to find if there was continuity between the two terminals from alternator to fuse box initially. With the audible output on the ohmeter (digital display is too slow), I could hear that there was intermittent (just the smallest) breaks sometimes when manipulating the terminal and wire.

Since then I have had no issues concerning intermittent battery charging and the light coming on. I have only put about 1k miles on it since but I am confident that particular issue is resolved.