Not being an electrickery wizard I can generally stumble through simple faults with some success however my bike is driving me nuts! It's not charging the battery at all and I'm at a loss to know why? I've looked at the alternator and the brushes are virtually new but when I put the multimeter across the battery terminals I'm only getting 11.5v with engine running @3000rpm 12.5v stationary and 11.5 with ignition on and engine stopped? So in as simple terms as possible (coz I'm really simple ) where do I stick the multimeter probes and what readings should I get to find the problem?
Thanks in advance, Paul D
They're rubbish them Jap bikes lad they won't last five minutes! you want to get yourself a nice Royal Enfield!
A quote from my old dad
I started out with nothing and I’ve got most of it left!
First, With the ignition ON, and the kill switch set to RUN, check to see if there is around 12v at the white wire terminal on the regulator. Second, with power off, check the continuity of the green wire from the alternator to the regulator. If either aren't correct, just make sure the connections aren't loose or corroded. If they are ok, make sure all three yellow wires from the alternator are checked for loose or corroded connections. If they are ok, you are left with either the regulator being faulty/misadjusted or the rectifier is faulty. Check by substitution if you have spares.Kev
Hi Just had this problem with my 550. Took every single connector out of the blocks from the alternator to the reg cleaned them shiny with wet n dry then sprayed with contact cleaner and carefully put it back together. Sorted mine but I know what you mean when you say its driving you mad!
Sounds like your battery is less than happy Paul.
Try a full charge before anything else as it shouldn't drop below 12v anyway.
Just put the multimeter leads directly on the two battery terminals for best volts readings.
Just a thought, did you clean all the earths?
Especially the one direct from the battery - clean the paint off the connections to the frame/engine.
Thanks Barney & Kev, looks like I'm going to be busy tomorrow, Alan, it's a new battery but I've been running around and fiddling with the bike for a few days since I charged it so that's probably that's why it's low? I've put it on charge overnight so with any luck I'll have a head start in the morning. All the earths are good and I've replaced earth and main positive leads as a precaution. I'll give you an update tomorrow guys thanks for your help.
They're rubbish them Jap bikes lad they won't last five minutes! you want to get yourself a nice Royal Enfield!
A quote from my old dad
I started out with nothing and I’ve got most of it left!
Do the measurements suggested by Kev. It won't be the battery volts, so long as you have at least 10v then the alternator field coils will work sufficiently to start producing power.
I doubt that it will be just one of the yellow wires as if one were broken then you would still be getting some charge out (it's a 3 phase system).
If you've never had it charging before I would also be checking for coninuity across the rotor and the stator coils. To do this disconnect everything and put a meter across the two slip rings that the brushes run on - you should have a few ohms resistance (it'll be in the manual, I don't have mine in front of me) - if that is ok then check for continuity between each yellow wire - again, unless all 3 are open circuit I wouldn't expect this to be the problem. In all the years I've run 750s I've had at least 3 rotors go open circuit on me, so I'm biased towards checking on that first!
I assume that the slip rings are clean? Oil would prevent the brushes from making contact...
If not any of the above then I'd be looking at the regulator - you can prise them open but you need to know what you're doing - there is a contact in there that can either get clagged up or even welded together. Be careful not to bend anything as otherwise you will need to readjust it for voltage regulation.
canaletto5 wrote:First, With the ignition ON, and the kill switch set to RUN, check to see if there is around 12v at the white wire terminal on the regulator. Second, with power off, check the continuity of the green wire from the alternator to the regulator. If either aren't correct, just make sure the connections aren't loose or corroded. If they are ok, make sure all three yellow wires from the alternator are checked for loose or corroded connections. If they are ok, you are left with either the regulator being faulty/misadjusted or the rectifier is faulty. Check by substitution if you have spares.Kev
Ok sorry for the delay but I've finally got round to checking my bikes electrics out
I can't see a white wire from the regulator? there is a black wire with a white trace is this the one? The green wire buzzes out ok.
I've checked the three yellow wires from the alternator and they seem to be fine. When I checked the slip rings for continuity (by which I think you mean no breaks so I get a reading?) and with the brushes in place the buzzer on my meter buzzes and with them removed it doesn't. Sorry if this doesn't make sense but I really struggle with electrics??
They're rubbish them Jap bikes lad they won't last five minutes! you want to get yourself a nice Royal Enfield!
A quote from my old dad
I started out with nothing and I’ve got most of it left!
Paul,
Please remind us, are you certain or not certain that the bike has been charging fine until now?
I ask because if you're not certain it was fine until recently, its possible that the fault lies entirely in a badly adjusted voltage regulator. For example if you've not ridden at night or ridden a long way, and put it on charge when you park up at home, you might not know if it was charging or not!
I've certainly had V-regs on test which looked dead on the bike (battery voltage no matter what the revs) but when I adjusted it, it then was fine.
There are two types of original Vreg, both adjustable. The one with the screwed on cover is easier, as it has a screw/locknut adjuster. The other has a tabbed on cover and you bend the contact to adjust the voltage.
Just wanted to eliminate one possibility!
Cheers,
Mike
Hi Mike, to be honest I don't think it's ever charged? I say this as I bought the bike as a U.S. Import and I've just basically cleaned it up put fresh tyres, fluids and a battery on it then MOT and register. The reg is the sealed type, at least I can't see any screws holding it together. I'll try and get some pics of the electric panel and alternator to give you an idea what I'm up against. Thanks, Paul
They're rubbish them Jap bikes lad they won't last five minutes! you want to get yourself a nice Royal Enfield!
A quote from my old dad
I started out with nothing and I’ve got most of it left!
canaletto5 wrote:First, With the ignition ON, and the kill switch set to RUN, check to see if there is around 12v at the white wire terminal on the regulator. Second, with power off, check the continuity of the green wire from the alternator to the regulator. If either aren't correct, just make sure the connections aren't loose or corroded. If they are ok, make sure all three yellow wires from the alternator are checked for loose or corroded connections. If they are ok, you are left with either the regulator being faulty/misadjusted or the rectifier is faulty. Check by substitution if you have spares.Kev
Ok sorry for the delay but I've finally got round to checking my bikes electrics out
I can't see a white wire from the regulator? there is a black wire with a white trace is this the one? The green wire buzzes out ok.
I've checked the three yellow wires from the alternator and they seem to be fine. When I checked the slip rings for continuity (by which I think you mean no breaks so I get a reading?) and with the brushes in place the buzzer on my meter buzzes and with them removed it doesn't. Sorry if this doesn't make sense but I really struggle with electrics??
Hi paul, sorry, it is the orange wire with a white tracer on it that needs to have battery voltage on it! There is no white wire there. Old age creeping in ! The black wire with white tracer is earth.
I can generally stumble through simple faults with some success however my bike is driving me nuts! It's not charging the battery at all and I'm at a loss to know why? I've looked at the alternator and the brushes are virtually new but when I put the multimeter across the battery terminals I'm only getting 11.5v with engine running @3000rpm 12.5v stationary and 11.5 with ignition on and engine stopped? So in as simple terms as possible (coz I'm really simple ) 
where do I stick the multimeter probes and what readings should I get to find the problem?
