[Not Charging] Alternator.. or something else

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glennvanlaerhoven

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Hi All,

I followed all the steps to try to figure out why mij vmax is not charging.

I found out that my starter relay is type:
MS5D 191
if i check the parts list it should be
MS5D 341.

I measured all cables from the stator, they all give 8 ohms.

If i measure the starter relay I get infinite.. (doenst matter which cable)

the bike starts fine tho!

Is this my problem before i replace this part?

thanks!
 
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The starter relay has nothing to do with the charging system. The vast majority of the time (i'm going to say 95%) it's a faulty voltage regulator.

Sean
 
oke that out of the way, if i measure this cable (blue ends) i measure 8 ohms. I guess this is the cable coming from the stator.

when i measure voltage on my meter. and check the cables with each other. I got zero.

Does this mean my stator is gone? Or do i measure wrong.

want to make sure I checked everything before I order new parts.



66C05326-A5D4-4A30-9A98-D4FC3BF5AF38.jpeg
 
I assume that you're measuring the bike's engine running when you measure for voltage? As I recall, the stator output should be something like 40-50 volts before the R/R. The reading you're getting for the ohms seems high.

Remember a R/R changes voltage from AC output to DC, to go to the battery.

I am not-aware there is any voltage on the stator wires with the engine off, and the key on. The rotor needs to be spinning for the stator to have an energized electrical field producing current. There is no connection to the stator from the battery, providing it with a current.

VMax Stator ohms reading.png
 
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Yes correct, Running and then the black pointer in 1 and 1 red pointer in anotherone. thats correct right? i dont have to put the black one to the frame.
 
Ha e you looked at the yamaha service manual - I'm pretty sure there will be a detailed description how to test all parts of the electrical system.

I have never seen those blue spade connectors on any production car or motorcycle so I ha e no idea what the wire goes to at the other end hence unable to help you.
 
thats the problem.. I’ve bought this bike like this. the white cables on the otherside (with connector) are going to the R/R. i need to verify if the R/R is faulty or the Stator. Thats why i need to be sure how to measure the stator.. And their is nothing to find in the manual.
 
Try this, the best charging fault finding doc I have.

Mark
 

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If battery is not charging then either the alternator is not producing electricity or the rectifier/regulator has failed.

I'm sure the service manual contains more details but here are pages from the Haynes. DSC_1357.JPGDSC_1359.JPGDSC_1358.JPGDSC_1356.JPG
 
It looks like someone has already been fighting this battle. Obviously those blue lugs are replacements and are a non-factory part. Not necessarily a bad thing, but it just suggests someone’s already been in there Chasing trouble.

Worst case, the stater is bad, it is far easier to replace than on some other motorcycles… Say a Honda GL for instance.

Follow documented troubleshooting procedures, but as Sean has pointed out, a very common point of failure in Vmax charging systems is the rectifier/regulator.
 
The check sheet that Mark has posted takes you through a guided diagnoisis and if followed you will get a first time fix.

Resist trying the 'best guess' alternative.
 
Try this, the best charging fault finding doc I have.

Mark
after testing with this document im now sure its the alternator.. if i rev it up to about 5000 rpm.. and i measure across the 3 white cables on voltage i got nothing..

I think i need to crack op the case and see what’s happening inside? Or any other ideas?

thanks so far!
 
after testing with this document im now sure its the alternator.. if i rev it up to about 5000 rpm.. and i measure across the 3 white cables on voltage i got nothing..

I think i need to crack op the case and see what’s happening inside? Or any other ideas?

thanks so far!
You just remove the left front engine side cover, we usually refer to 'cracking the cases' as removing the engine from the frame, and turning it upside-down to split the case halves.

The stator is a relatively easy removal/replacement. With no voltage from the three wires with the engine operating, it sure sounds like the stator.
 
I will post a pic tomorrow of how i meassure just to be sure im doing it the right way. but if i need to crack the case i will do it.
 
Have you also checked the stator resistance (measured between the three white wires)?
You should read 0.42 Ω +/- 15% at 20º C.
 
I meassured al 3 wires - 2 are 5 ohm and 1 is 8 ohm. After that I turned on the vmax and measured the cables again, 1 pin in the cables and 1 on the chassis and negative off the battery all zero..

2 possibilities left, pickup coil or stator..

if it was the pickup coil.. the vmax wouldn't start right? When I bought the motor, the guy has installed a new pickup coil(s) (mine is a 1990).
Is it possible that he didn't wire it properly? or didnt ground it? But if it was wrong would the vmax start?

Next to that, the vmax has a lot of backfire.. (carbs are rebuild etc, but not synced yet).. After reading some more on this forums.. this also could lead to the pickup coils.. or i just have to sync them.

Or is it the stator anyway?

Thanks for all the help already guys.. learned a lot already :)!
 

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As has been said above the pick-up coils have nothing to do with the charging system so I;m not sure why you are checking them.

after testing with this document I'm now sure its the alternator.. if i rev it up to about 5000 rpm.. and i measure across the 3 white cables on voltage i got nothing..

What scale did you have the meter set to?
 
I’ve read they could be a problem.. About the meter see the last picture. I tried multiple volt settings to check if I would get response.
 

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