XJ 600 84 model very low charging or non existant charging

Howdy guys.

Sam from Australia here, the proud new owner of a XJ 600 84 model with fairly low km's for its age. that is unless the odo has ticked over a couple of times.

Anyways, the previous owner was less then forthcoming about the bikes problems, he said there was just a bit of binding in the choke assembly as it doesnt seem to want to crank open fully, which is fine as the bike has no problem starting with 10-20% choke, but this makes me think its running rich, but that is not the problem for now, I can address that later.

The bike ran when I picked it up, I rode it about 60Km's and made it home no problems, but the next day when trying to kick it over on the starter it seemed sluggish and poor, but it still started.

decided to cruise down to the shops and back, bread and milk the usual, but when i pulled up to a set of lights and applied the brake, the bike seemed to start running very roughly (low spark!) and required a touch of throttle to keep turning over.

okay, no problem, so I took off from the lights, then as i put the indicator on to go into the driveway. the bike shuddered and stuttered each time the light came on, very scary business when your half leant over.

I realize there is a huge amount of information on here regarding regulators rectifiers and stator testing. but I've been having some trouble assimilating what I need to know in order to adequately diagnose this problem.

I have a brand new battery and another 'good' battery as well, both putting out a touch over 12.4v or thereabouts.

when starting and running the bike drops voltage down to about 12.2 or so.

there is no change at all when revving, if anything the voltage goes down slightly due to the higher demands of the coils from the battery.

this leads me to believe the regulator or the stator is stuffed.. so i tried to probe some of the white wires and whatnot, but this is where i get confused.

Should I be testing for AC on the white wires.. testing from the white to the ground? or from the white to the black wire? i know i should be getting 4-4.5v out of each leg of the stator but is it ac or dc volts right there. aka is it already regulated at that point.

I really dont have the money to rip the sidecover off the engine and purchase gaskets. so physically checking the stator is out for this week, but perhaps in a fortnight I can do so.

What about the connectors and cabling, to be honest this is my first wrangle with electrics and multimeters. so even a quick and dirty rundown on how check for continuity through the connectors would be nice as well. and what sort of resistance should i be looking at over each part of the bike.

I don't have a owners manual and with all the info on here I really don't feel it is needed right now, especially seeming as some people say the info is incorrect in there.

I would rather rely on what people have tried and works.

oh also, I went and lightly scrubbed up the fuse box connectors (original box) and checked if the connections were good across them, seemed okay. but i still am not sure as to which part of the multi im meant to be on. I used a little line thing with a --|>-- shape on it.

Sorry for the rambling post but I figure this gives you a good understanding of whats going on.

btw, when the battery is charged the bike starts and runs great. but it will run down over a few days and die on me.

one last thing, I know it doesnt show much about the bike but this gives you an idea of how easily it starts and runs.

XJ 600 starting

Thanks in advance for any and all help

 

Re: XJ 600 84 model very low charging or non existant chargi

Hi mate, you need a manual more than anything else!

Your bike will have the charging system which uses brushes to transfer the excitation current to the alternator rotor, rather than the 1989 onwards permanent magnet alternator. This means that it is the same as 95% of all the alternator questions here.

I can send you a PM regarding online manuals, but posting links to copyrighted materials is frowned upon on the site, so i will respect that.

The simplest way to test your alternator is to follow the proceedure in the manual. Make sure you have a circuit through the white wires, to each other (Test them in pairs) on the "Ohms" range. They should show 1 to 3 ohms from memory - check the specified settings.

You should get a circuit between the brown and green wires to. These are the rotor connections which go through the brushes/slip rings. Again, check the manual for the exact reading.

Don't forget to check the red wire coming out of the regulator is connected to 12v + on the battery.

If you have cleaned your connections, it is most likely to be brushes/dirty sliprings, regulator then stator in order of likelyhood.

Hope this helps, Mark

 

Re: XJ 600 84 model very low charging or non existant chargi

I will head on out to the bike and check that now. send the pm if you please.

I just don't have the time and patience to wait for a manual to be shipped.
(or the money either as funds are tight)

I just want it sweet so I can ride!!!! haha, its been about a year since I was up on two wheels. or one as the case usually was. so i just want to get the thing back up and running so i can clock up some k's.

 

Re: XJ 600 84 model very low charging or non existant chargi

bit dark to do much, but there was definately 12v coming through the red wire, will check resistances tommorow morning, approximately 10 hours from this post.

 

the alternator puts out AC volts. it's the job of the rectifier to convert to DC volts. if you probe the 3 wires that are the same color coming out of the motor. you should have a LOT more then 4v. the manual doesn't have an AC spec. but does give you resistance values to check. like the above posts state. 4v AC only means 4v DC hitting the battery.

check your wiring connections. some bikes are known to melt the connections in the charging system. check your brushes at the alternator. they might be worn out.

charging system should climb to at least 14v at the battery when throttle is revved to over 2k rpms. another way to tell is your headlight should also go a little brighter indicating higher charging to the battery.

 

On Bikes that have had some miles added-up on them, ... Alternator Brushes are found to be needing replacement.

Brushes of insufficient length begin to arc over a microscopic air-gap between the Brush and the Rotor's contact path.

The twin circular paths on the face of the Alternator Rotor become BURNED and discolored. The Alternator's power generating capability is vastly reduced.

Replacing the Brushes and "DRESSING" the twin race paths with a PUMICE Eraser will restore the Rotor surface in the case of LIGHT discoloration.

Pumice Erasers are getting hard to procure in a world where Typewriter Ribbons have become extinct.

 

Re: XJ 600 84 model very low charging or non existant chargi

I've sent you a pm.

 

Re: XJ 600 84 model very low charging or non existant chargi

Thanks for all the posts thus far, I shall be in and out of the house all day today wielding my multimeter.

I guess i got confused, I could have misread something on another post regarding the 4-4.5 volts.

So I follow those white wires down to the cover on the motor and check resistance there?

or should i check the white wires at the large quick connect on the regulator.

I would love to pull the side cover off and visually inspect the stator and whatnot, but this is impossible for now as I dont have the required goop and gaskets to put it back on.

 

Do all your testing at the multipin connector. The alternator cover should not need gaskets as there is no oil in there!

the stator (White wires) should be 0.3 to 0.4 ohms and the field (Green and brown) 2.7 - 3.3 ohms. If the field is not giving a reading, you'll have to carefully remove the alternator cover to inspect the brushes.

P.S. Don't you just love previous owners?

 

Re: XJ 600 84 model very low charging or non existant chargi

oh yeah, his exact words when i was purchasing the bike.. "Bring a helmet and ride away!" I guess he was right.. I did ride away.. but would have stopped after 100km. har har.

Back outside now with my piece of paper and all my things to check.
so glad its not a million degree's like it was yesterday.

edit, sorry i always assumed those covers required a seal or a gasket of some kind. and i read somewhere that the stator was in an 'oil bath' to keep it cool? guess i was misinformed yet again!

 

22 ohms resistance on the (sorry the field coil unit), pulling the stator cover off now to check further.

 

Okay, managed FINALLY to get the stupid connector off on the reg/rec. one of the prongs is melted fairly badly. thinking about just cutting it out and soldering it in, getting huge resistances through the connectors as they are badly corroded.will update once i've chopped and soldered it.

 

having alot of difficulty getting the side cover off.. any tips for difficult to remove screws?

 

fix the connectors. that might be your problem. before going any further in the disassembly process.

 

Use insulated spade crimps - or regular crimps with some heat shrink over the top, so they cannot accidentally touch each other. remember which colour wire goes where.

 

Re: XJ 600 84 model very low charging or non existant chargi

picking up some connectors tomorrow, going to drop solder into them after i crimp to make sure its 100% strong.

regarding the sidecover, at least i know that thing wont vibrate lose. damn those screws are tight.

 

High Tech:
Correct Allen Socket and Hand-held Impact Tool


Low Tech:
Correct Allen Wrench. Preload undo torque.
Smack with Hammer Handle.

 

Re: XJ 600 84 model very low charging or non existant chargi

its not an allen wrench type socket, its a phillips head (cross head) screw.

 

I just want to say a big thank you to everyone that has assisted on this site, you guys are awesome.

Im heading out to pick up the last few bits in an hour or two (7am so no shops open yet) then i should be done by midday and will update with any changes.

EXCITEMENT!!

 

iv got similar problem on my '89 xj600, what iv found so far and you need to check this aswell, i did all the resistance checks which were ok but when i put the meter across the battery it is 12.5v till i touch the brake light or put the lights on then it dives to 11.5v, so traced all wiring today and what i found was just under the bolt that holds the fuel tank on there is a 3pin plug with the 3 white wires from the alternator and that had melted across 2 of the connectors so shorted and seems to of killed the rectifier/regulator, iv sorted the burnt plug/wiring and im getting 0.3ohms across the 3 white cables and also 20v AC at the rec/regulator plug at 1100rpm and 50v AC when revved above 3000+rpm so genny seems ok, iv just ordered a new rec/regulator as i think the shorted plug killed it we will see when fitted but check that plug under the tank..