Stator and R/R test results.

Since I did more digging and testing I suspect my charging system on my XJ550 was to blame for my engine cutting out. I haven't cracked it open to test the rotor yet but so far here are the results for the stator. White leads were all .5 ohms across the board. Brown and Green lead tested in at 17.3 ohms.

R/R diode test was as follows
Positive to red, negative to whites
0, 0, 0
Negative to red, positive to whites
512, 510, 512
Positive to black, negative to whites
512, 510, 509
Negative to black, positive to whites
0, 0, 695

I know the .5 ohms is good for a 550, but I'm unsure on the brown and green reading. The diode test on the other hand isn't good. Biggest question I have is this since the R/R is hard wired into the harness instead of connected with the stock connector. Do the 3 white wires matter how they're connected to the wiring harness or are they specific to one another?

 

Phasing of the connectors should not matter, that is why each wire is white. I believe Len (info@xj4ever.com) sells the connectors so if you get a new Reg/Rect you won't have to cut the new connector off.

This is actually a bit high since you cannot disconnect the connector. The testing you did above should be done with the Reg/Rect isolated. Brown and green should give you the rotor resistance through the brushes if all is connected, which is specified to be at 4 ohms for the XJ650/750, most likely the same for the 550.

The reading of 695 could be OK if the connector is still mated. One phase of the 3 phase output is used to drive the headlight relay, so effectively getting a reading in both directions might be normal.

So did you fail step one in the process where the output across the battery should be 14.5V +/- .3 at 2K rpm or above?

 

Yes it failed the 14.5v test. I should have been more specific. I can disconnect the brown, green, and 3 white wires from the stator. Tonight after work I picked up a new multimeter after I found out my dad has let other family members who are less careful with test equipment use my old one. With the new one I got less than favorable readings on the stator of .7 ohms, .8 ohms, and .8 ohms on the 3 whites. On the brown and green its 16.5 ohms.

So it looks like I get to crack it all open and take a look at it all sometime this weekend.

 

Today on a break between shifts I finally got around to testing the rotor. At first I got a reading of higher than 5 ohms, and so I took one of my lens wipes to the contacts and got a solid 4.8. After finding some 100 grit emery cloth and giving it a light swipe the reading went down to 4.6 ohms. So I'm going on the hunch that my rotor is good, but needs to be polished up and cleaned. The one thing that bothers me is the inner contact ring on the rotor looks worn like wear marks I've seen on brake rotors. Not sure if that is normal or not. It looks like the PO used black RTV to seal up the cover so I have to fix that problem too.

I didn't do a direct test on the stator, but the connector still gave me .7, .8, and .8. And a test between all 3 to ground showed as open. So far my theory is the stator was damaged somehow and it fried the R/R. I'm going to get a new R/R, used stator and/or used rotor as a back up if I can find one for cheap. As for the R/R connector on the wiring harness side I'm going to hit a local motorcycle junkyard after the R/R arrives and try to find a usable one to splice in there.

That is unless someone else with more experience has some tips they want to throw my way before I begin parts ordering and hoarding?

 

100 grit is about ten times too rough, the rings should be glass smooth. clean them with a ink eraser. how are the brushes and springs? there shouldn't be enough oil in there to need sealed up.

 

One of the brushes is worn far more than the other is, and it doesn't appear to have oil in there. Lots of dust from the brush though. My father, someone who's dealt with electric brushes in various tools and electric motors over the years, said the rotor should be replaced. Hopefully the picture I've uploaded will be more helpful than my poor description skills.



I've found a few possible replacements on Ebay, but I'm not certain if a XJ550 Seca rotor will work as a replacement? The rotor itself has been tested at 4.7 ohms, but haven't yet gotten a reply on what the stator tests at yet.

 

550 seca engines are identical to the 550 maxim engines in all regards except the cams. the seca go hotter (more lift and duration) cams than the maxim got. so the ebay replacement should fit just fine.

FU

 

Thanks, went ahead and got the used rotor/stator combo, also went out and got 1500 grit sandpaper which I hope will do the polishing job, and last night I ordered a set of Rick's electric brushes.

All that leaves for me to do is hit the local motorcycle graveyard later for anything else minor that pops up.

 

I replaced rotor, brushes, and rectifier the other night. Started bike and it still wasn't charging, went ahead and swapped out the stator believing it was the cause. Today after I finally had time to finish fishing the stator wires back to their spot I once again tested for charging. Yet again I find out its still not charging. I even went as far as to test the voltage coming from the stator during idle/rev and both stay consistent through the range.

I admit I bought a cheap R/R from I believe it was Caltric on ebay. So now I can only assume the old stator may have damaged it(which is my fault), its simply a dud, or that the battery itself is fried and is somehow draining instead of charging and not causing any fluctuation on the voltmeter.

Then again when I wired in the 3 white wires they may have indeed been placemen specific and that is how its messed up..

 

The three wires from the stator do not need to be hooked up in any particular order. What is the voltage measured after the R/R at 2500 RPM?

 

That is the problem, the voltage starts off at roughly 11.80v measured at the battery and drops slowly no matter if its idling or at 2500 rpm.

When I first hooked up the new R/R(post rotor change, pre-stator swap) while running it became warm to the touch, which I've come to recognize as normal or at least something not to be to concerned with. I started it maybe 3 or 4 different times letting it run several minutes at a time while I did voltage readings. After that the R/R has remained cold to the touch, something that confused the hell out of me to say the least. Since then I've swapped out the stator, and of course I still have no charging on the battery.

The only thing different between now and before I did all the work is I've let the bike run a max of 40 minutes without it dying, where before after 15 minutes the battery would lose enough charge to cause the engine to bog down and eventually die if left alone.

 

Has the bike ever charged since you owned it? Just curious if the PO might have mis-wired something when the Reg/Rect connector was removed.

Have you done the voltage checks outlined in the service manual in regards to rotor excitation that is controlled by the Reg/Rect?

Did you get a connector, or did you have to hardwire the new Reg/Rect in place?

 

I did get a connector, so the Reg/Rect is removable once again. As for the charging, before I started all this work it did charge, but not to the required level with the old Reg/Rect on it. I'm going to go back and re-test the diodes on the old one again now that its been cut out just out of curiosity.

As for re-checking the rotor excitation it'll have to wait due to an incident involving a cat and a dog deciding the physical manual I had would make an excellent play toy tonight. Not sure if it was pure dumb luck, but at least they didn't get to the jumbo wiring diagrams I'd printed out for the XJ, and the Kawasaki KZ550 I have waiting in the wind as a minor project once I get the XJ in riding condition again.

 

A simple but basic check on the rotor excitation can be done with a feeler gauge. Take a thin feeler gauge and place it about a 1/2 inch away from the AC Generator cover, turn the key on and the feeler gauge should be drawn toward the cover as a result of the magnetic field in the rotor.

As for voltage checks, the service manual has you check excitation by measuring the voltage on the Brown wire (rotor power) at the Reg/Rect connector, which should be battery voltage and with a working unit, would measure 14.5V =/- .3V at 2K RPM and above. Since you know your not charging, then you should at least get battery voltage here, somewhere around 11.8V just with the key on and the bike not running.

The green wire (control) on the Reg/Rect connector per the manual should be less than 1.8V with the key on, and after starting should gradually rise as the engine speed is increased reducing the strength of the electromagnet, which effectively regulates the output of the generator. If this checks out at about 1V with the key on and the bike not running that would be a good sign the IC regulator is functioning.

 

Replacement Reg/Rect tested as battery at brown when on, and green tested as 10.3v. I'm going to say that the replacement is toast. Just on a whim I put the spare connector/spade terminals I bought on the old reg/rect and got the bike started. The old one read battery voltage on brown when on, and the green read .8v. Running old was 13.8v maximum on brown, and voltage dropped to .6v on green.

I'm going to replace the battery when I get a chance, and test the old reg/rect again. Then if I'm still not getting within spec I'll order another replacement reg/rect.

 

Definitely looks like the replacement IC regulator is toast.

13.8V on the brown wire is below the FSM spec, but that wire is subject to the voltage losses of a couple of connectors and the ignition switch. Plus, the battery should be fully charged when performing the test. Might be a good idea to fully charge the battery and then check the voltage directly across the battery to see if you get the 14.5 +/-.3V.

Little confused by that measurement. The green wire voltage should rise considerably above 2K RPM. The lower the voltage, the higher the current through the rotor. Guess it could be that the battery was not fully charged??

 

Plunked down the cash for a new battery, have it charging right now and with any luck I'll be able to test everything with a fully charged battery, or what I hope will be one anyway.

 

Also make certain the negative battery and earth grounds are good connections.

Gary H.

 

New results are this. Old Reg/Rect with a new battery is sticking out 14.43v at slightly above 2k rpm. I'm still getting that strange less than 1v reading on the green wire; the reading does change as the rpms increase, but it never goes above the voltage it initially starts at which is .7v. All these readings have been done to ground. Voltage across brown and green however stays at roughly 12v, but when throttle is applied it does change, dropping to 9v at the lowest. Not sure if that makes a difference.

I'll take strange but charging for the moment over not charging, and dying after 15 minutes which is what happened when I first started having these electrical problems.