Hi, owned my Z for quite a while now, I joined up here a while ago because it seemed like a very good source of information. I've searched and searched and i'm completely stuck now..

Today on a ride, my engine management light came on and the after stopping the bike it would not start again (Battery dead) Managed to get the bike back and discovered quickly that it wasn't charging. Checked out a few posts on here suggesting that the plug on the reg/rec could burn/corrode etc. Checked the plug and its absolutely fine.
After a few more head scratches, I checked the resistance on the stator which according to the manual should be between 0.224 and 0.336 ohms. I was getting 0.001 / 0.002 between the earth and both terminals of the stator plug. When I took the stator off to see if there was anything obviously wrong, I checked again and on the bench I was getting figures of 4.9 ohms where before I was getting virtually no resistance.

Now i'm really stuck, to be honest. A new stator is a little expensive and they don't usually go wrong. I've check everything else on the charging system and it all seems to be OK.

Want to get this sorted as i've got an off rod event in 20 days, and i dont want to miss out on that really lol

Any ideas/suggestions from anybody a little more electrical savvy would be hugely helpful

Cheers
Joe

and here is a quick obligatory pic

and to

You need to ask the Jedi Master, send a PM to Kev but you only get one session free from him, for more one to one session from Kev you would need to join the XT Supporters, have a little read on this link http://www.xt660.com/showthread.php?t=1475

Enjoy the forum

To be honest I was just about To pay a subscription now anyway - I've used the info on here non stop for a few months so it's about time I gave something back

cheers

Welcome on board Joe.

Sorry to here of your woes.

As you say, alternator stator failures are quite rare on bikes and I don't think I've ever heard of one going on an XT before? More often than not, a knackered stator when removed is visibly blackened and obviously goosed to the naked eye.

Your description of the test is a little confusing though...

There is no earth on the stator? There are three outputs, one for each of the phases and they are to all intents and purposes the same. None of these wires should have any continuity to earth, if there is then there's definitely a problem!

The resistance should be checked between phase 1 and 2, then 2 and 3, and finally 3 and 1, although it doesn't matter what the order is as long as you've got a reading from between each combination of terminal pairs. The telling thing is if all three are the same, and within the specified range. Although I think the service book states just to check 1+2 and 1+3 if I recall, which is a bit odd really because that won't tell the full story?

Another test you can do is check the AC voltage between 1 and 2, 2 and 3, 3 and 1 with engine running and the reg/rec unit connected. It's a bit fiddly to do because you need to be able to get at the three white stator coil wires at the back of the loom connector on the reg/rec unit whilst everything is connected up. It should be around the 17V mark for each phase, and again the telling thing is all three should be the same.

The third and final test (again with the stator in the bike) is to check each of the three phases (white wires) has no continuity to earth at all.

There's actually not that much it can be if the bike won't charge: bad regulator/rectifier unit, burned out/corroded reg/rec connector, failed stator coil(s), wiring fault, poor chassis earth, dead fuse, loose battery terminals or a knackered (shorted battery).

Good luck with it. I hope it's something simple (and cheap!)

__________________

I honestly cant think why i called one of the pins an earth.. But i have checked all three terminals as the service manual describes and as you have described (which is how i wouldve done it before reading the manual) turns out the stator is ok, i just had the meter in the wrong range and forgot to take the meter resistance into account when measuring. I got a bit spanner happy after a couple of beers and ended up taking the housing off along with the engine crash bars, the belly pan, and everything else, without thinking to check the actual output at the plug first but its at least given me chance to muck out all the nooks and crannies behind the cylinder, which ive been meaning to do for a while.

Anyway, theres nothing wrong with the stator and ive got hold of some better info on troubleshooting the whole system, so i'm gonna try that. After ive rebuilt it all lol.

Cheers for the tips, hopefully she should be working again after a few hours swearing at it tonight.

Joe

That usually does the trick ;-) Charging circuit is very simple - there are three wires from stator coils going in to regulator/rectifier supplying AC voltage, and two wires out supplying DC to the battery. You can wire the reg/rect up using patch wires and spade connectors to test that the reg/rect is working. If it's working using cables and spade connectors then there must be a break in the loom somewhere else causing malfunction. But try the swearing trick first :-)