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Discussion Starter #1 (Edited)
I had posted this originally in the engine forum, but it is electrical. The back story is that the bike would die whenever I turned the handlebars to the right. Several people suggested to check the left side wiring harnesses (makes complete sense, as it is adding strain there when turning left). I could not get the problem to duplicate yesterday, in the 95 degree heat, but I got it this morning when it was 70. Maybe the harness was more pliable yesterday in the heat. I have taken a video of the issue, and it has a relay like click when I get to the “dead zone”. Maybe kill switch? Maybe ignition? You’ll need audio for this, but it has a distinct relay sound coming from the right side of the bike. If the video doesn’t have sound for you, click the “v” in the lower left side of the video. It’ll take you to the page
https://vimeo.com/346534959

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2003 Vulcan 750/Sidecar
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Where is the relay for your coil mod? Is that it by the battery? Are the terminals fully insulated? No bare metal on the connections or pins?
 

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Discussion Starter #3 (Edited)
Where is the relay for your coil mod? Is that it by the battery? Are the terminals fully insulated? No bare metal on the connections or pins?


That is it by the battery. Where you have the washers and the bolt. They are not fully insulated, just the female connectors attached to the pin. I caught a sheet metal screw in the front tire, and I was going to get a patch kit from O’Reillys. I can get some heat shrink there. It sounds identical to the relay that turns on when the ignition is turned on. So that would make sense, since the rear coil is the trigger. To test, I should be able to disconnect the trigger from the relay to see if that is it.
Update - I pulled off the trigger and sure enough, it stopped doing that. So... is it as simple as insulating the female connectors? I just filled the tank, and I do not feel like draining it for the umpteenth time. I have a new petcock kit coming, so I will clean the fuel gauge, run new wire and see if that will fix that gremlin.


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2003 Vulcan 750/Sidecar
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Insulate the terminals by wrapping electrical tape around them and the relay. If the relay is loose and the bike only shuts off going up/down hill as you said in your previous thread the relay may be swinging and shorting against the frame.
 

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Discussion Starter #5
Insulate the terminals by wrapping electrical tape around them and the relay. If the relay is loose and the bike only shuts off going up/down hill as you said in your previous thread the relay may be swinging and shorting against the frame.


I will do that. The relay is tight though, and it felt like it would break if I pushed on it much harder to move it. It shuts off when turning the handle bars. So I think something is being stretched and grounding out.


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2003 Vulcan 750/Sidecar
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If the relay pins are exposed it might not take much movement to short it open. Wrap it and try it.

If no improvement, back to the wiring under the neck covers. You mentioned corroded wires. It may be you have a wire that is broken in the insulation and not visible as exposed. When you turn right it pulls apart in the insulation.
 

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Discussion Starter #7
If the relay pins are exposed it might not take much movement to short it open. Wrap it and try it.



If no improvement, back to the wiring under the neck covers. You mentioned corroded wires. It may be you have a wire that is broken in the insulation and not visible as exposed. When you turn right it pulls apart in the insulation.


It is grounding out the starter. The button does nothing after the relay clicks. I have insulated the whole mod very with electrical tape, but nothing works. The battery jumps up to 14vdc on idle and then drops to like 13.5 at 4K rpm. Thoughts? I have the stock r/r


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2003 Vulcan 750/Sidecar
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Working from faulty memory here. I think the coil wiring shows connecting the positive coil wire to the relay and on to the coils as connected to the starter relay positive. Try connecting that wire directly to the battery. Leave the relay trigger wires as is.

14v at idle when just started RR may be recovering the battery and then reving it is clipping voltage to a lower charging rate. If you battery shows 12.8V after sitting idle for 24 hours I wouldn't worry about stator/rr for now. Let's find the starting problem for now.

BTW, is the RR still under the battery box?
 

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Discussion Starter #9
Working from faulty memory here. I think the coil wiring shows connecting the positive coil wire to the relay and on to the coils as connected to the starter relay positive. Try connecting that wire directly to the battery. Leave the relay trigger wires as is.

14v at idle when just started RR may be recovering the battery and then reving it is clipping voltage to a lower charging rate. If you battery shows 12.8V after sitting idle for 24 hours I wouldn't worry about stator/rr for now. Let's find the starting problem for now.

BTW, is the RR still under the battery box?


Yes it is still in the stock location. I have the red wire that connects the two coils wired directly to the battery. That was the mistake I made before, I had it grounded


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2003 Vulcan 750/Sidecar
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About the battery voltages are those readings from when the bike would start?

Is the not starting intermittent or solid failure now?

Have you checked the battery voltage after sitting for a couple of hours. If so what was it? You have a wet cell battery if I recall correctly.
 

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Discussion Starter #11
About the battery voltages are those readings from when the bike would start?



Is the not starting intermittent or solid failure now?



Have you checked the battery voltage after sitting for a couple of hours. If so what was it? You have a wet cell battery if I recall correctly.


That was from when the bike would start. Before starting, it is at 12.38 and has been going up from there. That was after letting it sit for a few days. Yes, it is a wet cell battery. I wiggled all of the wires with the bars off to the right, to no avail.


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2003 Vulcan 750/Sidecar
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OK, you've wiggled the wires with no result.

With the bars to the right and the ignition on, are all the front lights, instrument and dash lights on?

With the run switch on an you hit the start button does the starter relay click?

Do you have a 3 amp charger? Can you charge the battery? Are all the cells to the full mark? O'Reiley's can load test it. And they have an AGM motorcycle battery for 85 bucks. I just had to replace mine.

After that it's back to tracing wires one by one for an open or short. All black/yellow should show ground.

If I recall, you don't have a meter just a continuity light. There' a way to use that but it's nasty! 8~)
 

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That was from when the bike would start. Before starting, it is at 12.38 and has been going up from there. That was after letting it sit for a few days. Yes, it is a wet cell battery. ....
12.4v is 50% charged, or half dead depending how you want to look at it.
 

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That was from when the bike would start. Before starting, it is at 12.38 and has been going up from there. That was after letting it sit for a few days. Yes, it is a wet cell battery. ....
12.4v is 50% charged, or half dead depending how you want to look at it.
I vote half dead, especially for a wet cell battery. I’ve learned the hard way how bad they suck.
 

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Discussion Starter #15
OK, you've wiggled the wires with no result.



With the bars to the right and the ignition on, are all the front lights, instrument and dash lights on?



With the run switch on an you hit the start button does the starter relay click?



Do you have a 3 amp charger? Can you charge the battery? Are all the cells to the full mark? O'Reiley's can load test it. And they have an AGM motorcycle battery for 85 bucks. I just had to replace mine.



After that it's back to tracing wires one by one for an open or short. All black/yellow should show ground.



If I recall, you don't have a meter just a continuity light. There' a way to use that but it's nasty! 8~)


All of the lights are on. I took apart the starter switch, which had corrosion, and cleaned that. So when I hit the spot on the range of motion (not all of the way to the right, it’s just a small little sliver that you can see in the video), the starter button will not work. Up until and past that, it works as it should. I will throw it on the charger, and I got a multimeter yesterday. I will have to get the agm, but this bike is turning into a money pit lol. I still need the brake lines, turn signals and fork seals. I have a new petcock rebuild kit coming, so once that comes in, and the tank is empty, I will take the tank off.

I also want to check the coolant lines when I have the tank off. It seemed that someone poured a ton of oil in the coolant reservoir. The rear cylinder coolant drain was plugged when I flushed the system. I think running the bike has dislodged the sludge, as there’s a film floating in the reservoir tank. Since I have had it running, the temp stays in the center, so I don’t think head gasket. I will reflush the system again.


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2003 Vulcan 750/Sidecar
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All "project" bikes are money pits. Mine was but when finished you'll love it. I do mine. Once I got past the noise these VN750 engines make that is! 8~)

With the bars at the dead spot continuity check all wires to start button and the run switch to see if you have an open that is pulling apart under stress.

Disconnect the battery, make sure the cells are topped off and charge it fully. Meter the voltage to see what the initial charge is. Let it sit disconnected for 4-5 hours for the surface charge to bleed off and meter again. Less than 12.8 is a weak battery.

The AGM battery seems to cure other issues. These bikes love volts at starting.
 

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For diagnosing starting/running issues I find it way better to just hook the bike up to a car battery with the car turned off. Those big car batteries can start the bike several more times and with better cold cranking amps than even the AGM batteries. That was how I figured out my last AGM was bad, and confirmed that there were no other electrical issues than the battery.

In this case it doesn't seem like the battery is necessarily the culprit, but may be discharged right now.
 

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For diagnosing starting/running issues I find it way better to just hook the bike up to a car battery with the car turned off. Those big car batteries can start the bike several more times and with better cold cranking amps than even the AGM batteries. That was how I figured out my last AGM was bad, and confirmed that there were no other electrical issues than the battery.

In this case it doesn't seem like the battery is necessarily the culprit, but may be discharged right now.
I don’t think the battery is your culprit either but it could just be a casualty. When my stator died last month I needed a few jumps to get the bike the 20 miles back home. That and I’m sure it sat long at the dealership where I got it fixed seemed to kill it. I was able to charge it but it didn’t hold it as well as it did before the stator crapping out. Using the bikes battery to troubleshoot electrical issue will strain it for sure
 

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Discussion Starter #19
Not to sound stupid, but I thought it was a 12v battery, so wouldn't 12.4 volts be spot on? I took it out tonight, and I think it is working the bugs out of the drive train. It is actually much more snappy than it was at first. I will take the tank off soon. I also saw the emgo wide swept handlebars. I wanted something that was similar to the road king (I think the handle bars feel perfect), so I am hoping these are it. Once I get back from my vacation, I will order those, and will probably have to lengthen the wires to get them to fit the wider handlebars.
 

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Not to sound stupid, but I thought it was a 12v battery, so wouldn't 12.4 volts be spot on? I took it out tonight, and I think it is working the bugs out of the drive train. It is actually much more snappy than it was at first. I will take the tank off soon. I also saw the emgo wide swept handlebars. I wanted something that was similar to the road king (I think the handle bars feel perfect), so I am hoping these are it. Once I get back from my vacation, I will order those, and will probably have to lengthen the wires to get them to fit the wider handlebars.
You don’t sound stupid, although I understand what it means it wasn’t something I was thinking about often until I got my bike

Check this scale
 
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