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V1000G5 - No Charge! |
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Jools 
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Joined: 19 Aug 2016 Location: Milton Keynes Status: Offline Points: 291 |
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 Topic: V1000G5 - No Charge!Posted: 27 Sep 2025 at 13:35 |
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I've lived with my G5 not charging the battery for quite a while, relying on putting the battery on charge before and after I go out for a ride. However, as the car died shortly after I left home today, I found myself with some unexpected free time!
Checking the status of the Rotor/Stator as per the suggestions on the Gutsibits website, I found the following; Rotor - (all wires disconnected, all terminals cleaned up) 1). Continuity - probes on slip rings = 4.4 Ohms (GB suggests ~ 4 Ohms) 2). Continuity - probes on spade terminals = 0.8 kOhms (GB suggests 4+ Ohms) 3). Insulation - probe on slip ring + probe on engine = 0.89 kOhms (GB suggests infinite resistance or very high resistance) The Stator checks out ok. I therefore suspect that my lack of charging from the alternator (I'm getting a maximum of 0.8 Volt) is due to the Rotor being defective, resistance readings 2 & 3 being somewhat wide of the mark according the the GB website info. I'm by no means an expert on electrics, so I would appreciate any comments as to my conclusion.
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Jools
V1000G5 1972 T150V 1961 Royal Enfield Constellation 1971 Suzuki ACC50 erm... 1963 Philips Panda (and other assorted detritus) |
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Brian UK
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Joined: 13 May 2014 Location: Surrey Status: Offline Points: 18226 |
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Posted: 27 Sep 2025 at 22:29 |
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If you are reading around 4 ohms between the slip rings, then the rotor winding is good. The much higher resistance seen between the spade terminals tells me that the problem is the brushes not making good contact or you have a problem between the spade terminals and brushes. As one slip ring is connected to earth if you still have the brushes connected, the insulation reading you are getting is showing the resistance through that brush to earth, not the actual insulation. To check the insulation, make sure the brushes do not contact either slip ring, then check between slip ring and engine case.
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Brian.
Better 5 minutes late in this world than years early in the next. |
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Mike H
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Joined: 21 May 2014 Location: East Anglia Status: Offline Points: 9053 |
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Posted: 28 Sep 2025 at 18:27 |
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+1 ... One slip-ring brush is grounded to engine, so meter probes across the brush connectors, and top connector (I think) to crankcase, should be the same 4 Ohms. It's looking like you might have a stuck brush, this happened to me on my BMW R80, same generator. I was able to remove it and scrape the sides a bit so it was free again, and put it back in the brush holder. I did this on a campsite ... which reminds me, be careful not to lose the curly spring that hold the brush in and presses it against the slip ring. (I didn't  )Edited by Mike H - 28 Sep 2025 at 18:30 |
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"Chicken nuggets don't dance on a Tuesday."
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Jools
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Joined: 19 Aug 2016 Location: Milton Keynes Status: Offline Points: 291 |
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Posted: 29 Sep 2025 at 21:32 |
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Right, round we go again! I repeated every test again to see if the results were any different. Here are the results;
Rotor - (tested with stator completely removed) 1). Slip ring to slip ring = 4.2 Ohms 2). Slip ring (front) to engine crankcase = 8 Mega Ohms 3). Slip ring (rear) to engine crankcase = 8 Mega Ohms Stator - (removed from engine) 1). Terminal D- to stator body = 0.4 Ohms 2). Terminal DF to stator body = Infinite resistance 3). Brush (front) to Terminal D- = 0.6 Ohms 4). Brush (rear) to Terminal DF = 0.5 Ohms 5). Terminal Y to Terminal U/V/W = 0.7/0.8/0.7 Ohms 6). Terminal U to V / V to W / U to W = 1.0/1.0/1.1 Ohms 7). Terminal Y to Terminal D- = Infinite resistance 8). Terminal D to Terminal DF = Infinite resistance 9). Terminal D- to Terminal U/V/W = Infinite resistance x 3 10). Terminal U/V/W to crankcase = Infinite resistance x 3 I think I've covered every permutation, and as far as I can see 'ain't nuffin' wrong'! But bolted back together and run up...... still no charging.... I've also checked the three leads coming out of the generator up to the diode array and all check out perfectly for continuity. With the engine running, measuring between each of the 3 leads shows less than 1 volt being generated. Surely there should be more than this, regardless of the functioning of the regulator/rectifier further down the line? So, the generator has to be the root of the problem somehow? |
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Jools
V1000G5 1972 T150V 1961 Royal Enfield Constellation 1971 Suzuki ACC50 erm... 1963 Philips Panda (and other assorted detritus) |
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Brian UK
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Posted: 30 Sep 2025 at 08:10 |
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You need to do the same measurement you did first time, disconnect the wires on D & DF on the alternator and measure the resistance between them. That's where you had a high resistance.
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Brian.
Better 5 minutes late in this world than years early in the next. |
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Gianni
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Posted: 30 Sep 2025 at 09:41 |
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With everything connected up, is there a red glow from your Gen light?
Is the Gen light bulb the correct wattage and resistence (i.e. you have not put an LED or something in there)? Is there a black wire from D- to earth (i.e. back into the loom and connected elsewhere)? This is fitted on some bikes and not strictly necessary, more of a belt and braces. What is the resistence between the battery negative and stator D- when everything is connected up? The purple (probably, may be brown on some years) wire connected to DF is a switched electrical feed from the regulator that modulates the electro-magnetic field generated in the rotor. So voltage from regulator to DF, to rotor slip ring in, through rotor, to rotor slip ring out, to D-. If the regulator is not working, you are getting no voltage so no field so no charge. If the brushes are not making correct contact then ditto. If the rotor is trashed then ditto. But all the above should show a red glow on the Gen light. Try GENTLY cleaning the slip rings with a green washing up pad, just enough to flatten them, not shiny.
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Le Mans 1, Spada, Cali 1, T3 Mongrel, Le Mans V, Quota x 2, Stelvio TT
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Jools
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Joined: 19 Aug 2016 Location: Milton Keynes Status: Offline Points: 291 |
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Posted: 30 Sep 2025 at 10:23 |
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The rotor checks out ok. The stator checks out ok. Ergo, there's nothing wrong with the generator.
Quite so, my dear Watson, so once you've discounted that, what else is there? Something I didn't perhaps entirely appreciate when I started this troubleshooting spree was that the generating system is not reliant on a permanent magnet, but on a switchable electro-magnet. That means that there needs to be a supply to energise the electro-magnet's coil - via Terminal DF in my case. So, was there a supply? No, there wasn't, and hence no generating capability. Lifting off the tank to trace the wiring back from the generator revealed a grubby blue box, high up between the frame rails. Underneath the grubby blue box was a grubby connector block. A disconnected connector block. Being impossible to view the insides of the box, my fingers found a series of spade terminals..... Oh dear Heaven, it really was that simple! Once reconnected, and with a cable tie to keep it firmly in place, normal service was resumed. A quick check of this supply would have saved me a deal of scrabbling about and head-scratching; something to maybe bear in mind if the charging fairies have gone AWOL! Nevertheless, thank you all for your helpfulness.
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Jools
V1000G5 1972 T150V 1961 Royal Enfield Constellation 1971 Suzuki ACC50 erm... 1963 Philips Panda (and other assorted detritus) |
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theone&onlymin
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Posted: 30 Sep 2025 at 10:34 |
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Was the blue box the regulator ?
Cheers Min
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Gianni
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Posted: 30 Sep 2025 at 12:48 |
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Some earlier electro-mechanical regulators had blue tape wrapped wround them to keep water out. The later, smaller electronic ones are potted in resin and do not need the tape but some had yellow tape to retain the fake high cover.
The regulators are Lucas NCB403 type and available cheaply from the usual sources. I believe they may be used on VW Beetles?
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Le Mans 1, Spada, Cali 1, T3 Mongrel, Le Mans V, Quota x 2, Stelvio TT
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Dukedesmo
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Posted: 30 Sep 2025 at 14:28 |
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Nice one, wish mine had been that easy when it stopped charging a few weeks back.
I had to get the rotor rewound - all good now it's done but could have done without the expense.
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Le Mans 2
Ducati 916 Ducati M900 |
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Mike H
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Posted: 30 Sep 2025 at 19:36 |
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Excellent! So all this time you could have simply plugged it back in, but didn't know it |
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"Chicken nuggets don't dance on a Tuesday."
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Jools
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Joined: 19 Aug 2016 Location: Milton Keynes Status: Offline Points: 291 |
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Posted: 30 Sep 2025 at 19:39 |
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The blue box must indeed be the regulator, though it's location took me by surprise. I rather thought that it should be with the rest of the electrics under the seat. Stupid really, as the bike was re-wired by a PO using their own 'highly individual' (read 'crap'!) system, bearing no obvious relation to any other loom in the known universe (even some of the contacts within the 'Lego' switches had been entirely removed!?).
I've always meant to do a proper re-wiring job, and got as far as getting one of Ken's laminated wiring diagrams, but no further. I guess that's down to my having more than 20 bikes - and every one a project if truth be told! Maybe time to re-arrange my priorities and get the job done...
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Jools
V1000G5 1972 T150V 1961 Royal Enfield Constellation 1971 Suzuki ACC50 erm... 1963 Philips Panda (and other assorted detritus) |
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AdrianW
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Posted: 01 Oct 2025 at 08:59 |
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>>I guess that's down to my having more than 20 bikes - and every one a project if truth be told!<< I'm down to 6 now (and one of those is new!) & I don't get much done on those that need attention (the other 5).... My V50 project has stalled a bit so I do sympathise..... Cheers, Adrian Bristol UK
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Mike H
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Posted: 05 Oct 2025 at 20:19 |
Oh piddle.  |
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"Chicken nuggets don't dance on a Tuesday."
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Jools wrote: