Disconnecting fuse stalls engine

Could be.......perhaps check and clean the brushes, then look for voltage drop at the usual suspects: key switch and fuse block
 
Just so we are om the same page here the adjuster has been adjusted as far as possible ?
But wont get the desired ca 14 V in the system
 
Older battery?
One year old Shorai lithium. I hadn't formally tested the battery prior to beginning my system checks, but the electric starter (i.e., decompression lever) worked fine. So I kinda doubt the battery's the issue.
 
Just so we are om the same page here the adjuster has been adjusted as far as possible ?
But wont get the desired ca 14 V in the system
Yes, it's currently just about all the way in. I don't like to adjust things to the max (or min), so I backed it out just a wee bit. But, essentially, it's maxed-out and not producing the proper volt readings (14.5+VDC). Another indicator to me that there's an issue there somewhere..
 
This may be relevant....
This component gets very hot within minutes of starting the engine. It's been like that for years, so I reckoned it's supposed to be that way. But perhaps not??
 

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Yes, it's currently just about all the way in. I don't like to adjust things to the max (or min), so I backed it out just a wee bit. But, essentially, it's maxed-out and not producing the proper volt readings (14.5+VDC). Another indicator to me that there's an issue there somewhere..
We have change in light intensity means charging we dont know if OK
We have a starter spinning. OK
Hot component that looks as the regulator

If this was me.
I would buy one electronic regulator as per Others recommendation what is Available in The US
I guess 10 - 15 Dollars .Hook that one up se what happens

The alternative is fault finding that can be time consuming and difficult.
Been doing that over the years.
I have had bad experiences with those mechanical regulators.

If the 15 dollars is nothing to accept I would measure the slip ring resistance on the rotor and report it here
so Mr Jim can have an opinion
 
I would buy one electronic regulator as per Others recommendation what is Available in The US
I guess 10 - 15 Dollars .Hook that one up se what happens
The alternative is fault finding that can be time consuming and difficult.
Been doing that over the years.
I have had bad experiences with those mechanical regulators.
If the 15 dollars is nothing to accept I would measure the slip ring resistance on the rotor and report it here
so Mr Jim can have an opinion
Thank you for the recommendation. I just ordered NOS OEM regulator and rectifier. A bit more than $15, but she's my baby, so...

Actually, I was troubleshooting the electrics as the final part of my end-of-season winterizing of the bike. It was really more of an afterthought so I wouldn't have to deal with it in the spring. I expected a quick/simple screw adjust to remedy the dimming (at idle) headlight issue and hadn't planned to be troubleshooting a new (fuse) issue. Unfortunately, she's now packed-up for the winter, so any further testing (at least until spring) is gonna have to be limited to those things I can test without much disassembly or starting the engine.
 
This may be relevant....
This component gets very hot within minutes of starting the engine. It's been like that for years, so I reckoned it's supposed to be that way. But perhaps not??
Yes, normal. That's the resistor current runs through on it's way to the rotor. It can (will) get too hot to touch.
H-light dim at idle and getting brighter when rev'd is also normal.
My opinion... the book way of testing is bullshit. I never pull the fuse. Just adjust the regulator until we get good voltage at about 3000rpm and it doesn't climb any higher after that. There's no logical reason for taking the battery out of the system (pulled fuse). Real world test/adjustment is almost always the preferred way.

Have a read here...

https://www.xs650.com/threads/rewound-alternator-rotor.54276/post-584935
 
Yes, normal. That's the resistor current runs through on it's way to the rotor. It can (will) get too hot to touch.
H-light dim at idle and getting brighter when rev'd is also normal.
My opinion... the book way of testing is bullshit. I never pull the fuse. Just adjust the regulator until we get good voltage at about 3000rpm and it doesn't climb any higher after that. There's no logical reason for taking the battery out of the system (pulled fuse). Real world test/adjustment is almost always the preferred way.
Have a read here...
https://www.xs650.com/threads/rewound-alternator-rotor.54276/post-584935
Thanks for the link, Jim. I've actually read (and followed) your guide before. It's been awhile tho'..

As to the system voltage: So I should NOT pull the fuse, but where do you recommend checking system voltage at? That is, where should I place the Fluke's + and - probes?

But back to the volt readings I was getting (prior to the fuse issue): The best I could get was a brief 14.1VDC @ ~ 2700RPM (close to 3k). So do I have a low volts problem....or no?
 
I have never pulled any fuses measuring
I Measure across battery
And 14.1 V I think is OK --- If lights is on .. I would check at above 3 k if slightly higher OK
If charging is low the battery will go low
And also if there is a short somewhere.
 
I have never pulled any fuses measuring
I Measure across battery
And 14.1 V I think is OK --- If lights is on .. I would check at above 3 k if slightly higher OK
If charging is low the battery will go low
And also if there is a short somewhere.
Unfortunately, because the Clymer guide I was following did not mention checking the volts with the headlight ON, I didn't do that. But it logically follows that if the light dims at idle, so do the volts. If I remember correctly, I think the idling volts were ~12.6~12.9-ish.

For whatever it's worth, the LED Charging Indicator I installed normally (i.e., with the headlight OFF) shows one green LED (i.e., good voltage). As soon as I switch the headlight ON, the green LED goes OFF and I get the first of the yellow LEDs ON (i.e., low voltage). However.....as soon as I rev the engine (~1500RPM+), I get a green LED again.

I don't know how accurate these LED indicators are, but, based on my Fluke numbers, I think it's certainly in the ballpark.
 

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You check directly at the battery. That's where we want the charge to go... no? ;)
Being just under 14v is low... anything over 13.5 is acceptable, but on the low side. 14 to 14.5v is ideal.
 
Being just under 14v is low... anything over 13.5 is acceptable, but on the low side. 14 to 14.5v is ideal.
Yeah, that's what I thought. So I was following the Clymer guide to achieve (closer to) the ideal.
Setting aside the new fuse issue and dimming headlight at idle, the bike's running perfectly. But that dimming headlight was bothering me. From yours and other comments here, perhaps it's not an issue???
 
From yours and other comments here, perhaps it's not an issue???
Nope, not at all. My bike charges perfectly at 14.4v. At idle it's 12.7-ish and the headlight is dim. Soon as I rev the engine it get bright. Perfectly normal.
 
Nope, not at all. My bike charges perfectly at 14.4v. At idle it's 12.7-ish and the headlight is dim. Soon as I rev the engine it get bright. Perfectly normal.
Many thanks, Jim.

However, there's still that (new) fuse issue. Although it may not be required to measure system volts (at the battery), something obviously changed or got damaged between the time the engine continued to run w/o the fuse and, now, where the engine stops as soon as it's disconnected. Any thoughts as to what component to check/point the finger at (the fuse itself is fine)?
 
Many thanks, Jim.

However, there's still that (new) fuse issue. Although it may not be required to measure system volts (at the battery), something obviously changed or got damaged between the time the engine continued to run w/o the fuse and, now, where the engine stops as soon as it's disconnected. Any thoughts as to what component to check/point the finger at?
Well, as I said your charge is a little on the low side. Acceptable, but low. Perhaps it's now low enough that it won't sustain the ignition at idle.
Try setting your idle up to about 2500rpm and then pull the fuse. See if it stays running?
 
Scenario: if idle voltage is a little low (~11 VDC) and the key switch has a little extra voltage drop (perhaps 1VDC), now the coil is seeing <10VDC and not enough spark to stay running:shrug:
 
Well, as I said your charge is a little on the low side. Acceptable, but low. Perhaps it's now low enough that it won't sustain the ignition at idle.
Try setting your idle up to about 2500rpm and then pull the fuse. See if it stays running?
As the bike's been winterized, I won't be able to re-check the fuse-pulling at 2500RPM 'til spring. But I'll definitely do that.

In the meantime, I do know that it was holding idle just fine before I shut it off for the winterizing over this past weekend. Again, the only problems were the dimming headlight (at idle) and the (new) fuse issue. Otherwise, she idles like a (happy) kitten and makes birds wish they drove Yamahas. :)
 
Scenario: if idle voltage is a little low (~11 VDC) and the key switch has a little extra voltage drop (perhaps 1VDC), now the coil is seeing <10VDC and not enough spark to stay running:shrug:
I think 11VDC is ALOT low. At that point, the LED charging indicator would be in the red, which I've never seen.
I'm pretty confident the idling volts wouldn't drop below 12V unless she were to sit for an extended period with the headlight high-beam on.
 
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