New xs400 problems.

I guess a question would have been good. It seems the bike is running rich judging by the completely black plugs. Should I down jet or just lean out the mixture screw? The only reason I ask is because it seems to run really well and I don't want to end up going backwards to a bike that runs like garbage. Before I jumped up to the 50's it was backfiring, popping and surging. So it is definately running alot better. I haven't really given it much throttle to test the high end yet (I don't have a tach yet), plus I'm having issues with scraping everything in the road so I've just been cruising. It does feel like there is a dead spot somewhere in the mid range though.

Also I have a relay on my bike that I can't figure out what it does, as far as I can tell its not on any of my wiring diagrams. Its got 2 red/whites, light blue and black/yellow. What does this do?
 
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Seems my charging issues have not gone away. I know alot of people are fighting the same problem right now so if you can chime in and point me in the right direction please do. Heres what I've done so far.

Swapped reg/rec from my other xs400
Tried bypassing reg (no changes in readings)
Checked field coil ohms (the readings were too erratic to determine what they were)
Checked the 3 white output leads (again the readings were all over the place)

With my meter hooked up to the bike and idling its somewhere around 12v, revving does nothing to change it. I did notice that as soon as I turned the bike off it charged back up to around 12.5-12.6.
 
Thats what I originally thought too, but this multimeter isn't terribly old. I will try another battery though.
 
If you can't get the resistance setting to work on your DMM you can measure the current into the field coil and the voltage across it while it has power. You can use those readings to figure out the resistance, R = V / I.
 
Im an idiot, I guess I had it on the wrong setting. Heres what I got.

Field Coil- 4.4
3 white output wires- 1.5
 
I rarely use the ohms side so it was bound to happen. Those readings don't seem too far off so I guess I can rule out the alt?
 
Those are good readings.

If you power your field coil by adding positive voltage to it directly from the battery terminal, you should see the volts go up.

Attach a wire to battery positive and then use a paperclip with a sharpened point attached to the other end of the wire (don't hold the metal, hold the rubber wire insulation) and use it to touch the wire to your field coil that sends it juice. (Usually green) at the socket that is under your tank usually. Should have green, black, yellow and blue wires. Add voltage to the green wire. This will send the voltage directly to the field coil, and you will see your overall battery voltage go upwards if the AC is being produced.

If the field coil is good it will magnetize and you can leave a single edged razor blade hanging there. It falls off when the coil is turned off.

that is the real test of your charging system. If it is being magnetized by the field coil and your stator is inside rotating, it will absolutely have to produce AC on the three white wires leaving the stator.

UNLESS they are worn or broken.
 
I may not have done it right. I disconnected my regulator and hooked direct current to the brown wire and grounded the green wire. I got a clicking sound which seemed to be the starter solenoid. Turned off the bike and it kept running until I disconnected the wires. My readings didn't change. Am I supposed to leave the reg hooked up during this test?
 
The short answer is "no". What happened after you turned it off was the power from the jump went through the regulator in reverse to the brown wires, essentially bypassing the ignition switch. The kill switch should have still worked though.
 
Send positive voltage down the green wire into the brushes in your alternator. Don't do anything to the black wire, it already flows to ground. See if your volts go up after that. They should slowly go upwards from wherever you are now to about 13 over a minute or so. If you rev the engine, it should go up further towards 14 volts. Don't exceed 14.5 volts. Go test this and see if you have a good alternator and then check back in please.

Do this on the socket that is at the end of the wires coming out of the rotor. They should be moving upwards from the alternator, behind the engine, routed behind the carburetors above the swingarm joint. You want to add voltage to the green wire as close to the alternator as possible, not through the wiring harness, but at the end where the socket is on the wires. Bypass any other wiring. Start the bike and see if the positive voltage activates the magnetism at your rotor/alternator.

Check back in when you're done.
 
Alright I added direct 12v to the green wire at the connector with the green,black,yellow,blue. I did not see any change in voltage in doing so.
 
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Check the AC voltage between each white wire and ground (I think mine read 20V AC), if they have a decent voltage then the rectifier or it's wiring must be dead. You can double check that by following the testing procedure in the manual.
 
Yeah, it's a treasure hunt for the problem. If you send volts down the wire into the coil make sure the the socket is still connected to the wiring so the black wire can carry to ground. You added it at the right spot though. The bike has to be running/rotor has to be spinning...

You will need to check your brushes physically now I think.

After that if they're not producing ac on the alternator, then you have broken wire/connection somewhere.
 
Checked the voltage on the white wires and the highest I got was like 1.2.

I may be wrong but I thought our bikes were brushless.
 
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Yep, no brushes on the alternator. I would check wires and components before diving into the engine, since it's not terribly likely that the coils are damaged if the resistance values are in spec. You might get away with gasket goo there, but I would opt for a new gasket if the old one gets ruined (a roll of gasket paper from Amazon is a good option).
 
I've been on the xs650 forum so much I forget which bike I'm referring to. xs 400 brushless. D'oh! (facepalm)

I made my gasket for my oil cover out of oaktag/file folder material. I have a template you can print out and make if you need. I sealed mine with a layer of red gasket seal and then trimmed the excess when I was done. Works fine. Buying and waiting for a gasket is silly. They're just stiff paper meant to fill the gap. Seal them with something and they'll be fine.

I think you have a broken or a shorting wire like most of us did. The most common place for it is as they emerge from the stator and enter the wiring cover which often hardens and turns into a rigid cutting object over time. With vibration it can saw through or dent/damage your wires emerging from your stator. Once they're compromised they can short to ground through oil on the wires. Mine did anyway.

Are you testing for magnetism at your stator/coil with engine running?
 
Another issue I found skimming all these posts was a misaligned stator will not produce the right amount of AC. Has your stator been removed and misaligned? It's a pain in the ass to remove it all the way because the edges were not ever rounded after they were cut. So they snag like crazy going in and out of the stator case, and to add to that, they're basically made out of stacked sheets of metal so they are in effect serrated. You'll see what I mean when you pull out the stator. Catch one of those stacked edges on the stator case sliding it down in and you'll regret the day you were born. I smoothed all my roughies off with sandpaper and now it slides in and out like a gem.

But check around the outer rim of it as it sits in the stator case and make sure none of the sides where the three bolts hold it down are much higher than the others.
 
It hasn't been removed by me since I've owned the bike so this will be my first time opening it up. I wanted to rule out everything else before popping that case off, but with my luck its never simple. So all I do is just remove all the bolts holding the case on and it comes right off exposing the stator?
 

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