79 xs650 not charging

[tmkenney]

Hello all! Im currently building a chopper from a frame/engine I picked up a few months back, and its going great. Its a 1979. Bike runs great and its tons ogreatly! I had to wire the bike from scratch, as it came with nothing and I've never had a bike like this before.

I bought the MikeXS regulator/rectifier unit for 70-79, and have it wired up how the description says.

Im having an issue where I'm not getting the bike to charge, maybe .1 volt past normal battery voltage when revved, but nothing really. I went through all the tests in the obvious big charging test post, and everything looks great. Getting 10.5ACV out of all 3 white wires at idle, and passed the feeler gauge slap test with flying colors. Resistances between slip rings and rings to ground also look good.

In my head, this points to a bad rectifier. But since its all one unit, id need to buy another altogether. Im worried that my deductions were wrong and I'm completely missing something, so any advice would be great!

 

[gggGary]

Lets see pic of inside the left cover.
Some pics of various charging circuits, possibilities.

 

[Its been a long time]

If I recall correctly, there's been quite a few posts about the Mike's combined reg/rec being dead on arrival. I suspect that's the problem.

I advocate a separate rectifier and automotive regulator. Cheap and reliable.

 

[Jan_P]

If I recall correctly, there's been quite a few posts about the Mike's combined reg/rec being dead on arrival. I suspect that's the problem.

I advocate a separate rectifier and automotive regulator. Cheap and reliable.

I Agree it is so cheap can have them in House a $ 25 --$ 35
If not that problem it is cost effective for using for fault finding Saving the man Hours in difficult analysis
And the rectifier is quick to fry if connect wrong
The auto ones are a bit larger and withstand better

I suppose the stock regulator and rectifier are not in house if there could try those

 

[tmkenney]

Lets see pic of inside the left cover.
Some pics of various charging circuits, possibilities.

View attachment 363131

View attachment 363132

View attachment 363133

View attachment 363134

View attachment 363135

View attachment 363137

Here's a picture of the stator with the cover off, as well as the unplugged connector coming from it. I just tested the rectifier this morning with a multimeter, and it seems like current is flowing correctly and only on one direction where appropriate. Im no longer sure that the rectifier is my problem unfortunately. Seems as though everything ought to be working perfectly based off my tests

 

[gggGary]

Here's a picture of the stator with the cover off, as well as the unplugged connector coming from it. I just tested the rectifier this morning with a multimeter, and it seems like current is flowing correctly and only on one direction where appropriate. Im no longer sure that the rectifier is my problem unfortunately. Seems as though everything ought to be working perfectly based off my tests

No pic as of yet.

 

[tmkenney]

No pic as of yet.

Apologies, let's try that again. Should be here. White wires connect to white on rectifier, black to ground and stator ground, green is to green on rectifier, red is to battery positive, and brown is to switched 12v.

 

[gggGary]

Ohm out the rings, should be in range of 5.2 to 6 ohms. Infinity to ground.
Leave your 6 prong connector open. Supply +12 to the outer (lower) brush, motor running you should see substantial AC voltage on all three white wires. 15 volts plus?
report.

 

[DaveO]

10.5v at idle sounds low to me. In spec is 10 - 20 with 50–70 VAC @ 3–4k rpm (er, i think)

 

[tmkenney]

Ohm out the rings, should be in range of 5.2 to 6 ohms. Infinity to ground.
Leave your 6 prong connector open. Supply +12 to the outer (lower) brush, motor running you should see substantial AC voltage on all three white wires. 15 volts plus?
report.

So when supplying 12v to the positive brush, im actually seeing between 5.5-6ACV on each wire constantly. Same with the connector plugged in and not supplying my own voltage. So I guess thats my issue, but now I wonder why its not putting out much juice? There's no shorts in the stator that I could find, and resistance between slip rings is 5.5ohm. And of course like I stated before, the brushes are brand new and installed right.

 

[gggGary]

OHM all three white leads, against each other then to the stator chassis (should be infinity).

Stator faults are rare but not unheard of.

 

[tmkenney]

OHM all three white leads, against each other then to the stator chassis (should be infinity).
View attachment 363185

Stator faults are rare but not unheard of.

So im seeing that each white wire ohm to each other is 1 ohm, but to ground each is about 1-1.5 mega ohm. Which tells me that the stator is shorted somewhere? Also update, just re tested and now each wire to ground is open lead. Hmmm

*update 2* wires will have different amounts of resistance to ground depending on which way I pull the harness. Looks like I overlooked a dumb issue and will be pulling the assembly out to go through and find the short. Im assuming something just rubbed through due to vibration long before I got ahold of the bike. Will update when I (hopefully) find and fix the short and see if it charges.

 

[gggGary]

So im seeing that each white wire ohm to each other is 1 ohm, but to ground each is about 1-1.5 mega ohm. Which tells me that the stator is shorted somewhere? Also update, just re tested and now each wire to ground is open lead. Hmmm

*update 2* wires will have different amounts of resistance to ground depending on which way I pull the harness. Looks like I overlooked a dumb issue and will be pulling the assembly out to go through and find the short. Im assuming something just rubbed through due to vibration long before I got ahold of the bike. Will update when I (hopefully) find and fix the short and see if it charges.

Look especially where the harness goes past the sprocket, that's a common trouble spot.

 

[tmkenney]

Look especially where the harness goes past the sprocket, that's a common trouble spot.

So everything looks good up until the stator. Slightly corroded where it enters the windings, and if I hold test leads to the wires and the body of the stator, I get continuity on/off when I wiggle the wires around. So seems like the wires are rubbing through right where they connect, which is a bummer. Assuming this means Its smoked and I need a new stator?

Would be very cool if I could remove the winnings assembly from that housing to further inspect/attempt to fix, but im not sure how it comes apart or if it does at all.

 

[Its been a long time]

That's your problem, for sure.

 

[siscoken]

So im seeing that each white wire ohm to each other is 1 ohm, but to ground each is about 1-1.5 mega ohm. Which tells me that the stator is shorted somewhere? Also update, just re tested and now each wire to ground is open lead. Hmmm

*update 2* wires will have different amounts of resistance to ground depending on which way I pull the harness. Looks like I overlooked a dumb issue and will be pulling the assembly out to go through and find the short. Im assuming something just rubbed through due to vibration long before I got ahold of the bike. Will update when I (hopefully) find and fix the short and see if it charges.

Don't be fooled by the mega ohm reading .... thar could be the reading of resistance thru your body if you are touching components.... that is a vey high reading.
My reading thru my fingers

 

[tmkenney]

Unfortunately, got a new/used stator that was confirmed good, and bike still does not charge more than .02 volts at a time, so still basically nothing. At my wits end here, I've tested every single component 5 times and it should be working well. Im very close to just buying a PMA kit, but I doubt that would work if this doesnt.

 

[Jim]

I bought the MikeXS regulator/rectifier unit for 70-79, and have it wired up how the description says.

Unfortunately, new doesn't always equate to good. It wouldn't be the first Mikes reg/rec that was bad right out of the box.
In Tech there's a thread on making your own reg/rec for way less than the cost of the Mikes one. I think I'd go that route instead of trying to make Mikes Chinese crap work.

https://www.xs650.com/threads/diy-reg-rec-5twins-and-jim.55842/

 

[Its been a long time]

If I recall correctly, there's been quite a few posts about the Mike's combined reg/rec being dead on arrival. I suspect that's the problem.

I advocate a separate rectifier and automotive regulator. Cheap and reliable.

Worth repeating myself.

As per the link in Jim's post above.

 

[tmkenney]

Unfortunately, new doesn't always equate to good. It wouldn't be the first Mikes reg/rec that was bad right out of the box.
In Tech there's a thread on making your own reg/rec for way less than the cost of the Mikes one. I think I'd go that route instead of trying to make Mikes Chinese crap work.

https://www.xs650.com/threads/diy-reg-rec-5twins-and-jim.55842/

Got it thanks! I'll take another look at that. I did a few more tests, and after having a known good stator put on, I can now say the regulator is junk. 10.9 volts going to the positive brush with key on, and 8ish volts at the brush with bike running. When I supply the brush with full battery power and rev the bike, it charges at 15 volts. So it seems 100% certain that the regulator is my current problem.