Bike stalls at stop lights? Carb or electrical?

I have no bullet connectors. Everything is soldered. There is a small ground going from the actual negative side of the headlight to a rivet on the headlight bucket. My original ground was attached to the screw on the headlight ring. Apparently this ground was no good. Can this resistance be causing my charging strain? I'm going to drill a larger hole into the headlight bucket and run a ground straight to the negative terminal on the light tomorrow.
 
No it's not that the resistance is causing charging strain but it sounds like you may not have a good ground.

So check your solder joints, and double check wherever you have your system tied to ground.

Your grounds should all read 0 to ground.
 
I double checked all the other grounds and they're at 0. DAMN! I was hoping this would solve my problem. Oh well! I'll be checking the stator legs tomorrow, something I should have done a week ago.
 
Well for the alternator really, your most likely candidates are your ground wires and your brushes. Unless disturbed your stator wires aren't likely to just break.

Sorry if you already said this but with no battery connected, what is your resistance at the brush tops (i.e. brush - > rotor -> brush )

it's a good test. Those brushes are one of your few moving parts.
 
rotate the engine and keep an eye on that reading, see if you have any dead spots.

that sounds about right though.
 
Joe, measure the ground from the where the negative cable bolt's to the frame to the engine. On my 650, I had a bad ground there, where the engine bolt's to the frame, and caused me to burn up 3 rotor's. That could be part of the problem, beside's the ground's in the headlite. How I solved my engine ground was to put a heavy wire from one of the cam chain adjuster bolt's directly to the negative connection at the frame. I routed it up through the carb's so it's not really visable. You could make a separate ground to the headlite .
 
I just started to do Curly's test today and he's where I'm at so far. Keep in mind that I charge to 14.5 without lights on.

1. Battery 12.6
2. passed with the feeler gauge test.
3. Jumped to ground--- Nothing
4.Voltage at battery 12.57. Voltage at Brown Brush 12.22
5. 5.9 ohm between(should be 5 to 5.5) and infinity from slip rings to engine.

I somehow managed to strip out the brush bolt and I'm going to the hardware store to get another one. Hopefully I didn't strip out the brushholder too.
I also checked dc voltage(I know I should have checked AC) at the white wires and I found an inconsistency in the results. I was getting 7.8 on two whites and 11.7 on the third. Any idea what this means and if it relates to my hassles?
 
Gordon said:
Joe, measure the ground from the where the negative cable bolt's to the frame to the engine. On my 650, I had a bad ground there, where the engine bolt's to the frame, and caused me to burn up 3 rotor's. That could be part of the problem, beside's the ground's in the headlite. How I solved my engine ground was to put a heavy wire from one of the cam chain adjuster bolt's directly to the negative connection at the frame. I routed it up through the carb's so it's not really visable. You could make a separate ground to the headlite .
Click to expand...

5977638029_439379a1cc_b.jpg

Here's where the large ground that attaches to my starter. I know if doesn't look secure but it is. It's also just temporary since I pulled everything apart today. It's gettin 0.0 resistance. I have another ground going from my battery terminal to the other side of the battery box. Same resistance. The battery I'm using is a small battery from 650 central and the positive and negative wires aren't very thick. Maybe like 18G wire. I soldered a thicker wire to the negative lead an added a butt connector so I can charge up the battery. I'm using 14 guage wire from the other end of the butt connector to ground on the other side of the battery box.
 
18 ga. wire from the battery? There is your problem, should be at least 6 ga. You can't get enough amperage through an 18 ga. wire to run the system, let alone a headlite. I am surprised that they haven't burned up.
 
section8joe said:
I just started to do Curly's test today and he's where I'm at so far. Keep in mind that I charge to 14.5 without lights on.

1. Battery 12.6
2. passed with the feeler gauge test.
3. Jumped to ground--- Nothing
4.Voltage at battery 12.57. Voltage at Brown Brush 12.22
5. 5.9 ohm between(should be 5 to 5.5) and infinity from slip rings to engine.
Click to expand...

I retapped the brush holder and got everything back up and running. Here's the last of the charging system test:

6. I should have been getting around 10.5 and 11 AC volts between each white wire. My readings were lower
Between 1 and 2= 7 volts, 1 and 3=8 volts and 2 and 3=7.5 volts
7. Test results should be between .4 and .5 ohms and my findings were pretty close. I got .6,.5 and.4 ohms.

Test 7 also says that
"If the readings are now good then the yellow wire or safety relay are shorted. If there is one or more that still read low after disconnecting the yellow then check those legs by touching one lead to ground with the other on the white wire. You should see a very high Kilo ohm or infinite reading. If you get a low resistance check the stator lead pigtail to see if it is pinched by the cases or rubbed through on the frame. If that looks ok then your stator is shorted and needs to be replaced. "

I assume that since my yellow wire is unplugged and capped of I have a short somewhere in the yellow wire? Is there something I'm missing? I believe I followed everything correctly.
 
I had a very similar issue, nearly every time I pulled up at lights it stalled, I also got the occasional miss fire.

I traced mine to the ignition switch, I was checking the wiring and when I unbolted the switch form the mounting the switch was starting to seperate, a new switch sorted it out, it was obviously shorting out. I had a carb issue too but ignition switch was the main culprit.
 
I was thinking since that yellow wire isn't doing anything I can cut it close to the stator and cap it off so it doesn't cause any problems? Would that short cause low AC voltage from the stator wires?
 
I not sure what your situation is but when i built my bike i ran all my grounds to the negative on the battery. Its alot hard to get a bad ground that way. Plus the ground for your head light shouldn't effect your charging as much as it would effect the light itself. The low AC voltage on your legs means you have two weak fields in your stator could be causing your problems. Look into the banshee setup thats where im heading to next and it should diffidently fix your problem.
 
All of my grounds are going to the negative battery then to the frame. The only ground that isn't grounding in that spot is the heavy ground from the starter. I'm gathering parts for the PMA swap as we speak. I just want to ride this thing now. Planning on doing the pma swap in the winter.

Anyway, I checked the yellow wire for continuity to ground and the other 3 white wires. No continuity to ground but I did have continuity to the three other white wires. Am I checking for the yellow wire short the wrong way? Is my stator shot? Any suggestions? I do apologize for the dumb questions I'm learning as I go.
 
Last edited:
To check the stator windings for a ground, you need to first unplug the yellow wire connector that comes up by itself from the alternator. With the connector unplugged, measure the resistance from any one of the white wires to ground (use a high resistance scale.) Should measure infinity "I". If you measure a low resistance then the statorwindings are touching the casing at some point.

I pulled that from another thread and I gave it a try today. I'm getting .4 and .5 ohms on all my white wires. I'm getting no resistance from my yellow to ground. I'm thinking that since I'm getting nearly .5 ohms that my stator is grounded and it's shot. What do you guys think? Is there anything else I can try?
 
Joe, those reading's are good IF your testing white to white to white. Check from white to the case it sit's in, that should not have ANY continuity. I have tested them before with houshold current(115 ac). One lead one the white's, the other to the case. I was shown this by a guy who has a rebuilder's shop. He said that once in a while, when the stater is questionable, that's how he would test them because the high voltage would search out any flaw's.
 

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