Dies at night

WelderDave

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So Friday I drove around with buddies all day without an issue. Ten before sundown we stopped at a club for a few hours. When we left it was dark and I drove about half mile before the bike started to die out and couldn’t keep it running. Had a 1.3ah battery and harness could have been better.

Took the next 2 days and made new legit harness with solder, heat shrinking and the whole 9 yards.
Today we took the bikes out and they said it had some smoke when I really hammered her, and the plugs show no signs of oil. But the bike does run really well for the mikesxs carbs. Then again, after dark we finally stopped at a bar for food, stayed an hour or so, then started back up and not 15 minutes I. The ride it starts doing it again. But now I have a legit motorcycle battery in it. Lights start flickering like the first time and it just starts dieing. Randomly cuts out.
I can dump the clutch to get it back and let it idle before the lights stop flickering and then I can ride a bit before it bogs out again. All that happened both times, difference is the second time I got a huge backfire probably because it wasn’t igniting the mixture and dumping fuel in the exhaust.

Stator wires ohmed out at 1 ohm but while running during the day it runs fine and shows ~15v charging the battery. I don’t understand what this issue could be. Runs good all day, park it, sundown comes and then it starts fine and then just bogs out, lights flicker, and dies.

Anyone have any ideas?

I’m about ready to blow this thing to pieces.
 
What is about 15v exactly. I wonder if your regulator or rectifier is overcharging and cooking your battery?

Obviously time of day erroneous to your problem. It's the rides then doesn't pattern. Test what the testing charge on these batteries are. Did they smell like sulphur?
 
There’s no sulfuric smell or anything. I was just talking to my buddy who works on bikes and their neighbor who’s an electrical engineer and they said with the symptoms it’s having and what they tested it’s either the regulator or the stator that’s going. I guess there is a place around here that will rewind it for pretty cheap, and I could look for a new regulator rectifier, but the one is new and figured I should do the stator first.
 
Yes. Can install voltage meter to better diagnose. I have a battery tender lead on mine and there is an attachment to that for voltage which makes it easy to check and you can see of it's getting charged, over charged (regulator), or just draining during ride (stator).
 
Check all wires for frays or loose connections. Those stator wires are in a bad spot and can get oil soaked and ruined.

You should read around 14.5v at 3000rpm but no more than 15v.


If your bike has a condenser, might be worth checking that out. Easy way to check is to look for excessive sparks coming from points.
 
So I jumpered power to the field coil and grounded the other end and it read battery voltage, there was no jump so it’s not really charging. Last time I did this was last year and it jumped up quite a bit. I’m thinking stator is basically gone.

Local place here rebuilds alternators and winding of sorts and will test it and rewind it if needed. So I’m gonna start pulling it tomorrow. Anywhere I can buy new gaskets for the stator cover and that round cover that’s on the stator cover without buying a whole engine gasket set?
 
So took the stator and field coil all out and brought them to the local shop that Specializes in rebuilds on electrical charging systems and they tested them out and said everything was perfectly fine. So the only thing left is the rectifier. The company wants me to test it first beforehand, and it’s out of warranty but only has 300 miles on it so I’m hoping they will give me a discount on a new one.
 
Well, good news and bad news. Good news is after following their testing instructions for th reg/rec unit, it tested good and I don’t need to buy another one. Bad news is, I don’t know what’s wrong then.
Gonna go through with a dvom on the rest of the charging system. These bikes vibrate a lot so something may have come loose causing an intermittent connection coming loose.

For good measure I cut the original connector off from the stator and field coil and bought a new one to solder in place. The old connector has seen better days, and was like that when I bought it but I’m wondering if something went wrong or corrosion just got to it.

I’ll let everyone know what I ended up doing and how I fixed it once I get my other parts in and tighten everything with a little lock tight.
Got a buddy that works on military vehicles said they rtv all connections after everything has been secured, tested, and verified to work, so I think I’m gonna do that also.

It’s gonna end up being something stupid, I just know it, but at least I know my parts are all good, which makes it a inexpensive repair.
 
Smart to redo connector. Loose ground cables are a common fault in electrics but seems weird yours would work then not then work. Also double check no loose fuses. And invest in cheap voltage meter if you need to further diagnose so can monitor its activity during rides. They aren't that expensive to begin with and super easy to wire.
 
Very true, haven’t thought of that, I should invest in one to monitor the battery. Also great for diagnosing without having to break out the dvom. Grounds ave been all solid, checked those first. I’m using a grounding block which makes it easy. Fuses and connectors to them are all tight and new, but I’m thinking the screws for the key cylinder started coming loose wich supplies all the main power from battery to sense wire too. The original stator connector was definitely corroded, but when I get over there I’ll be ohming it out to see what it actually read out of curiosity.

Edit: bought a handlebar mounted voltmeter with a usb charge port. Should be a nice addition!
 
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Well, you’re never gonna believe this. Everything was wired and working correctly, I just blew a fuse... I had a main fuse between the rectifier output and battery positive, and it’s inline and tucked away, so I forgot all about it until tonight. It had a 20 amp fuse in it because I forgot to swap it to 30amp. So just waiting for Monday when the gasket kit comes in and I can put the rest back together and re solder it all. Won’t make that mistake again.
 
Well, you’re never gonna believe this. Everything was wired and working correctly, I just blew a fuse... I had a main fuse between the rectifier output and battery positive, and it’s inline and tucked away, so I forgot all about it until tonight. It had a 20 amp fuse in it because I forgot to swap it to 30amp. So just waiting for Monday when the gasket kit comes in and I can put the rest back together and re solder it all. Won’t make that mistake again.

20 amp seems high for that fuse. Really need that much? Stock is 20 amp main with 10 amp on the remaining 3 circuits. I don't know at what point the wires will melt since they would mainly rated for a specific current draw.
 
Depending on your wiring I would consider eliminating that fuse.
Shouldn't be any fuse between the rectifier and battery. The battery is supposed to sink excess voltage from the stator. If it blows again you could start seeing electrical damage.
 
Depending on your wiring I would consider eliminating that fuse.
Shouldn't be any fuse between the rectifier and battery. The battery is supposed to sink excess voltage from the stator. If it blows again you could start seeing electrical damage.

On the stock wiring diagram what I see is one red wire coming from the rectifier up to a 10 amp fuse and from the 10 amp fuse over to the ignition coils and the battery. I assume for charing purposes. Now I could be looking at the diagram wrong. But that's what I see.
 
Glad you found it. Frustrating but at least an easy fix! Everybody has done something mindlessly similar.

Consider the above replies and study the factory diagram to determine appropriate action
 
On the stock wiring diagram what I see is one red wire coming from the rectifier up to a 10 amp fuse and from the 10 amp fuse over to the ignition coils and the battery. I assume for charing purposes. Now I could be looking at the diagram wrong. But that's what I see.
Looks like it varies by model. Later years appear to have switched to having the rectifier tied directly to the battery.
 
Looks like it varies by model. Later years appear to have switched to having the rectifier tied directly to the battery.

Yeah if thats the case in this case then certainly I would say remove the fuse. Assuming nothing else had changed with the wiring.
 
Yeah I guess the reason my fuse popped was the battery couldn’t sustain a load and it overcharged and I’m assuming it boiled the battery. Got a new battery and it was sheathing at 18.5v at 5k rpms so I bought the r292 and gotta hook that up yet. Hopefully that solves my problem
 
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