1990 XJ600 melted rectifier

I recently bought a 1990 XJ600 which came with a blown rectifier , I purchased the appropriate part (OEM) for the model, fitted it and 150 km's of short trips later it basically melted, (picture liquid solder dripping out onto the ground and main fuse blowing .)
I've had the battery tested and it is holding charge and being charged , the recifier is the right part for the model .
I'm new to bike mechanics so can only deal on a fairly basic level.

Something must have caused the recifier to overheat and 'melt', before I go putting another one in there, and have the same thing happen again (Kiss another $105 good bye)
, I wondered if anyone can offer suggestions on what to check and how to check it .

I read somewhere a suggestion to check the alternator , how do you do this , there are only 3 white wires and 1 red wire going into the recitifier I think this model has a brushless alternator .
I also have a 1985 XJ600 for rebuilding that I could take parts off but the recifier on this model has 7 wires and I believe it has a different alternator

Can you Help? thanks from Wellington New Zealand

 

I would start checking your wiring harness from front to back and make sure you aren't shorting somewhere. Also make sure you are using the correct amp fuses. I would say there is a short somewhere.

 

My bet is a bad stator.

 

I dunno what caused that but that is a major short! Unlikely to be the stator though. Its usually a bad regulator/rectifier that causes the stator to fail. These items are common enough and you don't have to go OEM. Discuss with your local auto electrician. Cheper options are available!

See:

http://forums.overclockers.com.au/showt ... p?t=800788

http://web.archive.org/web/200712140435 ... html#alter

This last link is Triumph related but have a look because it will give you a great grounding on bike electrics and a lot of excellent pictures

http://www.triumphrat.net/speed-triple- ... grade.html

 

Have a real close look at the Quick Connector that the Regulator Plugs-into.

If the Connector shows signs of MELT or Overheating, ... examine the Connection very closely.

Often, during an Overheat situation, ... the Connector HEATS sufficiently to let the LOCKING TAB on the Wire's TERMINAL End to let the Terminal "UN-seat" and the Connections to the Terminals Plugged-into it to remain OPEN or have such a High Resistance to cause a re-occurrence of the Short.

 

IIRC, you shouldn't have any continuity between any of the three white wires going to the stator and any other of those wires.

Also you should not have any continuity from any of them to ground.

When running, each should show 1/3 of the output voltage when a voltmeter is connected between one of them and ground. So you'd want to see 4-4.5v idling each, more as rpms increase.

I like Rick's suggestion though...I've seen that cause problems too. Suzuki LC's are known for it.

 

A stator has three phases that are insulated from the stator frame and from each other. The 3 wires go to the rectifier where AC current is converted to DC current, then on to the regulater. When 1 or more phases short with the frame or each other it results in a blown rectifier. This can also be caused by shorted wires from stator to rectifier. Almost never does a bad rectifier cause damage to the stator unless it is continued to operate for a extended time.

 

Thanks for all the suggestions so far , you have given me some good things to check . I'll try them in the week end and let you know what I find . With a 20 year old bike it makes it sound like running new cables from the stator to the recifier would be a good idea .

Let me know if you have any other suggestions ,
Thanks

 

The New Recifier I put in was one I got in ebay auction 360283519091.
Anyone know any source for a cheaper or better recifier than this ? It ended up costing me $105 NZD by the time I got it to New Zealand which was pretty cheap considering I was quoted $350 NZD for an original Yamaha part by a local dealer and $250 NZD for a generic part plus labour cost to convert it to fit by a local bike shop.
The one off ebay had the right connector and fitted the same mounts and I am told was the right part for the model based on the frame number

 

That was a good price. I did PM you - I used a second hand 5 terminal (4 will work to) regulator rectifier from the 600 diversion (Called a "Seca2" in the US). Check my gallery for a picture/the connections.

I paid £15 !!!!

 

OK so I started doing the checks suggested , The connector has no sign of melting though the locking pin on the red wire doesn't seem to hold it and the wires moves around a bit (the female end).
Continuity between the white wires to the stator, there is clear continuity from white wire to white wire, from each white wire to earth it doesn't 'beep' but there is about 5mm movement in the needle on the multimeter indicating something is there, this is with -ve probe on white wire and +ve probe on frame.
I took the alternator cover off and the Stator doesn't look good to me , Picture in my gallery, what do you think? would the stator be the cause ?
To get the stator and cable out do you have to remove gear shifter lever and cover to get at wire?

thanks

 

That stator looks pretty fried.

Did those coil stacks get pushed together from removal, or is that how you found them?

At any rate, those two towers look heat damaged on top...I bet that's you problem...it went from three phase to one phase...your continuity checks seem to support that...

 

Seat the RED Wire and place a Drop of Epoxy to it's back side in the Connection ... to make-sure that RED Wire doesn't have it's Terminal -- "Pushed-Out" of the Quik-Connect when you Plug-in the Regulator

 

Unless the Stator is very fragile I assume the bent coil stacks were already there, I have never taken a Bike alternator apart before , so was fairly careful pulling it apart,

The delimma I have now have is , is the damaged Stator a symptom or a cause ?

What would cause that sort of damage to the Stator ? If I replace the Stator and put another rectifer in it will the damage just happen again if I haven't identified to original problem or cause.

Melted Recifier, fried Stator which came first?

I do know the recifier was disconnected when I bought it , and the guy I bought it off knew it was stuffed and used to charge the battery every couple of days when he was using it since the battery wasn't getting charged .
Also the main fuse is supposed to be 30 amps , someone before me had fitted a 45amp fuse I think because at some stage the main fuse kept blowing .
When the recifier melted for me the main fuse blew and with the melted recifier still connected everytime I changed the main fuse it would blow again when I tried to start the bike . I assumed the melted Recifier was shorted.

 

I've seen Melted Connectors at the Voltage Regulator Harness Joint and Fried Voltage Regulators from situations where the Bike got hooked-up to a SUV that had the Engine running.

I don't know what the Voltage and Amps were during the Jump attempt.
The Voltage Regulator was hot and the Connector where the Regulator Plugs-into the Wiring Harness got melted.

I don't know what the Conditions are to cause the Overload or Short.
The damage was limited to the Regulator and Wiring Connection.

 

Hi Markie,

re readings between the 3 wires from the stator

The Haynes manual says

Alternator.- Stator coil resistance - 0.31 to 0.37 ohms at 20 degrees celcius

I'm not completely sure how to use the ohms scale on my mulimeter,
I took readings from wires 1 to 2, 1 to 3, and 2 to 3.
when using the x10k setting it measured 0.5ohms for all 3
when using the x1 setting it measured 4, 4 & 4.2
when using the x100 setting it measured 1.7 for all 3

this was all at 7.6 degrees celcius (we are having a cold snap )

Is this good/ bad?

 

You should be using the X1 range. The temperature will have a small effect on the reading but not that much. Connect the red and black together and deduct that reading from the coil resistance value. If the leads measure 2 ohms - take away 2 from the stator reading.

The values sound worng (Too high) but I dont have my 600 anymore to compare with.

Can another 600 owner check their values and post them here?

I'm a bit worried by your 45 amp main fuse - 45 amps is an awful lot!!

 

I pulled out the 45amp fuse and put in the recommended 30 amp main fuse when I got it . It wasn't solving anything just masking a potential problem.

 

Where are we at with this? As suggested it may be worth while visiting an auto electrician for his opinion? Have you read the links I posted? What does the previous owner know about the start of all this?

 

I would not be at all surprised to hear that this Bike had a Dead Battery at one time and was repeatedly Jump-Started.

I think that there is a condition in hooking-up to another vehicles battery that the Voltage Regulator can't handle and gets fried.

 

The 2 most common cause for a bad stator are: 1. Bad or defective bearings/bushings that support the ends of the rotor/armature allowing it to drag the inside edge of the stator causing a short. 2. Insulation on the phase wiring of the stator has deteriorated due to excessive use and/or age causing a short.

In short, it was a short. :lol:

 

Was this sorted?

 

I also melted my old rectifier and it was caused by 2 of the 3 white ac cables from the genny shorting out at the 3 pin plug located under the cross menber where the tank bolts on near the battery, i did all the various tests before i found the prob, my voltages etc were:
ac volts across the 3 whites 18vac tickover to 50vac over 2500rpm.
resistance across the 3 whites was 0.3ohm.
after i found the shorted cables and sorted the wiring i fitted a new rectifier off ebay £36 inc p&p all ok after.
Voltage across the battery at tick over 12.2vdc put lights on and it goes up to 14.2vdc.
1990 ( H reg) xj600