XS2 Not Charging

5twins said:
There are other adjustments on your voltage regulator besides that screw. There is a core gap and a point gap that must be within the given spec for the unit to perform properly .....
Click to expand...

Thanks, 5twins. Unfortunately, the regulator in the bike appears to be working properly (the readings I got match the specs in the troubleshooting procedure in the Yamaha service manual), so I have to presume it's gaps aren't too far off, if at all. However, I have a second (NOS) regulator and both gaps differed, slightly, from your diagram. So I corrected them.

Do you have anything additional for the OEM rectifier? That's the component that flunks the service manual troubleshooting tests. I just returned an OEM-style rectifier that was passing current in both directions and I've got another one here (photo above) that's supposedly NOS, but clearly isn't. Anyway, based on the readings, two of the diodes are slightly off and the third is open, which is why I went ahead and started putting together the diy version in the preceding post.
 
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Sorry, nothing on the rectifier. Mine's been OK so I never had to mess with it. If it did go belly up, I'd be building one like you are. Once you get the bike charging again, tweaking the regulator can give you the optimal output (about 14 to 14.4 volts when revved to 3K) you desire.
 
A (Strange) UPDATE: I took the bridge rectifier assembly I'm building (photos above) over to the bike to do a test fit (no problem there). Since I was there, I reckoned I might as well bring the rectifier in the bike back home with me and test it again. Now, here's the strange part: now it tests OK. I'm getting 5ohms between the red & three white alternator wires in one direction and infinity in the other direction. Same results between the black & three white alternator wires. I don't get it?! Did I get it wrong? Are you supposed to test these components out of the bike?

Two days ago, when I initially tested the rectifier three times! (in the bike) with the same Fluke digital multi-meter I'm using now (its battery is good), one of the three white alternator wires always read infinity, in both directions and with both the red or black wires. I can't remember the exact readings of the other two white alternator wires, but they were similarly to each other but not to spec.

What gives? Now I don't know what's going on at all or whether I even need to build this diy rectifier??? Can anyone make any sense of this?
 
freddy3 said:
A (Strange) UPDATE: I took the bridge rectifier assembly I'm building (photos above) over to the bike to do a test fit (no problem there). Since I was there, I reckoned I might as well bring the rectifier in the bike back home with me and test it again. Now, here's the strange part: now it tests OK. I'm getting 5ohms between the red & three white alternator wires in one direction and infinity in the other direction. Same results between the black & three white alternator wires. I don't get it?! Did I get it wrong? Are you supposed to test these components out of the bike?

Two days ago, when I initially tested the rectifier three times! (in the bike) with the same Fluke digital multi-meter I'm using now (its battery is good), one of the three white alternator wires always read infinity, in both directions and with both the red or black wires. I can't remember the exact readings of the other two white alternator wires, but they were similarly to each other but not to spec.

What gives? Now I don't know what's going on at all or whether I even need to build this diy rectifier??? Can anyone make any sense of this?
Click to expand...

Its an old electrical component, so it may have intermittant faults. Best to just let it die; its glory days are over. Carry on and make up a new one, as it will give you good results.
 
I guess that's possible, so I'll soldier on and report back with results, hopefully this weekend. Thanks again.
 
UPDATE (of sorts): Unfortunately, Mikesxs failed to ship the needed connector for the diy rectifier 2nd-day after I ordered it on Wednesday (according to the tracking page, it's scheduled for delivery Monday), so I haven't yet been able to test it yet. So, I'll have to report back with the results of the diy rectifier in a few days.

However, I stopped into the storage where I keep the bike today and happened to have my digital meter with me (remembering that I had another good regulator at the storage with the bike), so I stopped by and performed a couple more ad hoc tests:

First, I swapped-out the existing regulator (which tested OK, both per the Yamaha service manual and the core and point gaps in 5twins' illustration) for the NOS regulator and rechecked the volts at the battery @ 2500rpm. Still 13.15VDC.

Second, I disconnected the regulator connector (so the regulator's completely out of the circuit), restarted the engine and rechecked the volts at the battery @ 2500rpm. Again, still 13.15VDC. In fact, at any engine speed above idle (~1200rpm), it's always 13.15VDC.

So the problem seems to be in some component ahead of the regulator.
Again, the system passes the slap test and I've installed new brushes (and cleaned the tracks on the rotor face).

Does any of this new info re the regulator spark any epiphanies?
 
freddy3 said:
UPDATE (of sorts): Unfortunately, Mikesxs failed to ship the needed connector for the diy rectifier 2nd-day after I ordered it on Wednesday (according to the tracking page, it's scheduled for delivery Monday), so I haven't yet been able to test it yet. So, I'll have to report back with the results of the diy rectifier in a few days.

However, I stopped into the storage where I keep the bike today and happened to have my digital meter with me (remembering that I had another good regulator at the storage with the bike), so I stopped by and performed a couple more ad hoc tests:

First, I swapped-out the existing regulator (which tested OK, both per the Yamaha service manual and the core and point gaps in 5twins' illustration) for the NOS regulator and rechecked the volts at the battery @ 2500rpm. Still 13.15VDC.

Second, I disconnected the regulator connector (so the regulator's completely out of the circuit), restarted the engine and rechecked the volts at the battery @ 2500rpm. Again, still 13.15VDC. In fact, at any engine speed above idle (~1200rpm), it's always 13.15VDC.

So the problem seems to be in some component ahead of the regulator.
Again, the system passes the slap test and I've installed new brushes (and cleaned the tracks on the rotor face).

Does any of this new info re the regulator spark any epiphanies?
Click to expand...

Another simple test is to measure the voltage at the brush terminals. With the engine idling at about 1200 rpm, the regulator should produce about 10 to 12 volts at the brush terminals. I know you did the slap test, but you need proper voltage at the brushes in order to produce a strong magnetic field. With a working charging system, the brush voltage will drop back to around 6 or 7 volts as you rev the engine to 3000 rpm.

You could also measure the current flow to the rotor, by disconnecting the green wire on the outer brush, and placing your VOM in series. Current should be around 2 amps.
 
retiredgentleman said:
Another simple test is to measure the voltage at the brush terminals. With the engine idling at about 1200 rpm, the regulator should produce about 10 to 12 volts at the brush terminals. I know you did the slap test, but you need proper voltage at the brushes in order to produce a strong magnetic field. With a working charging system, the brush voltage will drop back to around 6 or 7 volts as you rev the engine to 3000 rpm.
Click to expand...
Just so I'm clear, (engine idling) I remove the round cover over the brushes and put the plus lead from the VOM on one of the brushes and the negative lead from the VOM on the other brush. I should see 11~12 volts. Correct?

You could also measure the current flow to the rotor, by disconnecting the green wire on the outer brush, and placing your VOM in series. Current should be around 2 amps.
Click to expand...
Okay, I think I got it. I'll try these two tests and report back.
Thanks again.
 
freddy3 said:
Just so I'm clear, (engine idling) I remove the round cover over the brushes and put the plus lead from the VOM on one of the brushes and the negative lead from the VOM on the other brush. I should see 11~12 volts. Correct?


Okay, I think I got it. I'll try these two tests and report back.
Thanks again.
Click to expand...

That's correct.
 
Measuring voltage across the brushes - 0. Yes, no voltage across the brushes, in either direction with the engine idling at ~1200rpm (or up to 2500rpm, which I tested as well).
Measuring amps (with the VOM in series) on the green brush wire - 4.54.
Measuring amps (with the VOM in series) on the black brush wire - 5.00.

Just wondering....
Are there any wires inside the headlight case that, if shorted or disconnected, could cause this?
The reason I ask is because the problem began right after I replaced the tachometer, which required me to unscrew the ignition (key) switch and take both the tach and speedo harnesses out of the headlight case in order to have enough room to get the [new] tach harness in. Just in case the key switch is in a different location on your bike, this is how it's layed-out on the XS2:
xs2_nos_speedo&tach.jpg



I removed the two phillips head screws below the ignition (key) switch and just lifted the switch to the side. Then, I removed the old tach and lifted the speedo up and set it to the side while I removed the harnesses from both instruments. Then I fed the new tach's harness into the headlight case. There was alotta pulling and tugging since the holes in the rear of the case make it a tight fit. I was careful not to put alot of stress on any of the wires and I've checked a couple times to be sure nothing got (or was left) disconnected (nothing was). But since the electrics died about 45 minutes into my first ride (a few hours) after I finished installing the new tach....
 
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freddy3 said:
Measuring voltage across the brushes - 0. Yes, no voltage across the brushes, in either direction with the engine idling at ~1200rpm (or up to 2500rpm, which I tested as well).
Measuring amps (with the VOM in series) on the green brush wire - 4.54.
Measuring amps (with the VOM in series) on the black brush wire - 5.00.

Just wondering....
Are there any wires inside the headlight case that, if shorted or disconnected, could cause this?
The reason I ask is because the problem began right after I replaced the tachometer, which required me to unscrew the ignition (key) switch and take both the tach and speedo harnesses out of the headlight case in order to have enough room to get the [new] tach harness in. Just in case the key switch is in a different location on your bike, this is how it's layed-out on the XS2:
xs2_nos_speedo&tach.jpg



I removed the two phillips head screws below the ignition (key) switch and just lifted the switch to the side. Then, I removed the old tach and lifted the speedo up and set it to the side while I removed the harnesses from both instruments. Then I fed the new tach's harness into the headlight case. There was alotta pulling and tugging since the holes in the rear of the case make it a tight fit. I was careful not to put alot of stress on any of the wires and I've checked a couple times to be sure nothing got (or was left) disconnected (nothing was). But since the electrics died about 45 minutes into my first ride (a few hours) after I finished installing the new tach....
Click to expand...

In the earlier posts there has been no mention of the rotor resistance.With charging problems, the brushes are the first thing to check, closely followed by a resistance check of the rotor winding.Your readings at the brushes are not looking good. 4.5 or 5 amps indicates the rotor resistance is down to approximately 2.8 ohm. Rotor normally should be 5 to 6 ohms. Half the winding would be shorted out, and would give a partial magnetic field.

In order to have 4.5 to 5 amps flowing, you must have 12 or 13 volts across the brushes. How you could measure 0 volts, would be a mystery to me.:shrug:

Measure the rotor resistance, to see what is happening.
 
Yeah, I was pretty stunned to see 0 volts at the brushes, but I definitely had the VOM set to VDC with each of its test leads on each of the brush wires and, because I was so amazed to see 0 volts, I checked it three or four times, each with the same 0 volt reading.

Good point re the rotor readings. I remember now. The VOM's battery died as I began doing readings and I meant to go back and check the rotor (and stator), but the thread went in a different direction and I forgot to do them. It's supposed to rain the next day or two, but I'll get back to the storage unit and check the rotor/stator numbers in a coupla days. Sorry about that.
 
UPDATE:
Rotor tests Okay (6 ohms between each slip ring, infinity between each slip ring and rotor core), but I'm getting 0 ohms resistance (i.e., shorting) between any of the three white wires at the connector and the stator housing.

For reference, I'm getting 0.7 ohms between any two white wires, which is within spec. Also, I'm getting the proper readings between the brushes and their associated green and black brush wires at the connector (0 ohms).

So it looks like my two year-old Mikesxs stator's gone south on me. And, correct me if I'm wrong (or missed something else), but it looks like I need to order another stator.

Again, is there anything inside the headlight case that could've damaged the stator? The bike had been running beautifully until right after I replaced the tachometer. The bike died (with a new/dead battery) just minutes into my first ride right after I finished the tach install!
 
freddy3 said:
UPDATE:
Rotor tests Okay (6 ohms between each slip ring, infinity between each slip ring and rotor core), but I'm getting 0 ohms resistance (i.e., shorting) between any of the three white wires at the connector and the stator housing.

For reference, I'm getting 0.7 ohms between any two white wires, which is within spec. Also, I'm getting the proper readings between the brushes and their associated green and black brush wires at the connector (0 ohms).

So it looks like my two year-old Mikesxs stator's gone south on me. And, correct me if I'm wrong (or missed something else), but it looks like I need to order another stator.

Again, is there anything inside the headlight case that could've damaged the stator? The bike had been running beautifully until right after I replaced the tachometer. The bike died (with a new/dead battery) just minutes into my first ride right after I finished the tach install!
Click to expand...

Yes, if you get 0 ohms from the white leads (stator windings) to the stator housing, then that stator is bad, and needs to be replaced.
 
I might consider getting your stator rewound. Call Gary at Custom Rewinds. 1-800-798-7282 I think he has a warranty on his work, Mike's doesn't.
They list the 75-79 on the web site. I think the 70-74 used the same stator. If it don't then he can rewind yours.
Leo
 
I've already ordered the stator from Mikesxs and I'd reckon that total turn-around time to get my stator rewound and returned to me from Gary will be considerably more than the few days it'll take to receive a new one from Mikesxs. That said, I'll ring Gary and see about having the current one rewound as a back-up (which, considering my history with these things, is probably a good idea).
Thank you.
 

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