starts, idles, revs great, but misses under load above 2k

[Flyinfool]

It it were me...I'd have one person handling the meter probes, the other gently rotating the harnesses (the 3 whites) and the RR outlet one at a time to try and recapture the 14.8 V scenario.

 

 

Have you ever performed the stator ground test with the engine hot? Trying to understand why you had a great RR side reading of 14.8 V then when you try next time its back to square one.

Wondering if heat soak is opening a short in the stator.

:sign yeah that:

We seem to be chasing a moving target, as in an intermittent connection some where.

Try hooking the volt meter up across the battery, set the engine to 3000, then start shaking and wiggling the wire harnesses along with some pulling on the wires at the connectors, to see if you can make the voltage change, or the engine miss. Whether it goes up or down don't matter at this point, it should not change no matter how much you massage the wires.

[Razorback]

 

At idle i saw the voltmeter dip when applying the brake (hand or foot).

 

 

I had thought i was having an issue when stopping at intersections based on engine dropping to idle, when actually it was due to applying the brake. At the sam time, I also thought the voltage was recovering based on engine speed. It's actually recovering because I let go of the brake at the same time i accelerate from a stop.

 

I mentioned this to a guy here at work and he says i definitely have a short in my brake system.

Makes sense.

 

I've had the back of my bike off several times over the last few months with carb/fuel tank work going on. Maybe i compromised a wire or connector to the brakes and/or running lights in the process.

 

I'll dig into that when i get home. Didn't ride today due to rain.

 

After I get that checked out, I'll get some helpers and start wiggling wires.

[Neil86]

Well even on a healthy 1300 with the electric antidives you will see a slight dip on voltmeter with brakes on...factor in a bad charging system or connections and it gets worse.

 

You are seeing voltage dips as you go down the road too...are the brake lights coming on for no reason?

[Razorback]

You are seeing voltage dips as you go down the road too...are the brake lights coming on for no reason?

 

 

Not that I'm aware of. I suppose I can use one of my 12V leds and hook in to the circuit and monitor from the dash.

 

 

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[Flyinfool]

If there were a short in the brake circuit it would blow the fuse and no longer pull the voltage down. But that is not what is happening. Between the low output at idle and the amount of power required to activate the anti dives and the brake lights, that is enough to cause a voltage drop. A weak connection in the charging circuit will also cause the brakes to drop the voltage more than normal.

 

It is still my opinion that you need to solve the charging issue before delving into any other issues. A weak or intermittent charging system does many weird things.

[Razorback]

If there were a short in the brake circuit it would blow the fuse and no longer pull the voltage down. But that is not what is happening. Between the low output at idle and the amount of power required to activate the anti dives and the brake lights, that is enough to cause a voltage drop. A weak connection in the charging circuit will also cause the brakes to drop the voltage more than normal.

 

It is still my opinion that you need to solve the charging issue before delving into any other issues. A weak or intermittent charging system does many weird things.

 

 

Yep, just wondering if the proposed brake system voltage drop was affected the overall charging system performance.

 

I'm on my way home to giggle wires😁

 

 

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[Razorback]

Check this out: I have a meter back probing the RR connector and my voltage at idle is 14.08 at 1000 rpms. If I rev it gently to 3000, the voltage will drop to about 12.9-13.0. I let it return to idle and the volts come back up to 14.

What would explain that?

 

 

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[Razorback]

It it were me...I'd have one person handling the meter probes, the other gently rotating the harnesses (the 3 whites) and the RR outlet one at a time to try and recapture the 14.8 V scenario.

 

 

Have you ever performed the stator ground test with the engine hot? Trying to understand why you had a great RR side reading of 14.8 V then when you try next time its back to square one.

Wondering if heat soak is opening a short in the stator.

 

I forget on the stator test, motor off - probe stator leads to engine ground?

[Neil86]

Engine off

Stator Connector (3 whites) unplugged from RR

Test between stator whites and a good ground

should be open to ground

[Neil86]

You might want to verify your ground point is good....ie test it vs the battery negative

for low resistance...or use the battery negative as the ground point in the test.

[Razorback]

Here's the video on YouTube, demonstrating the voltage drop as i rev the engine to 3000 rpm.

 

 

 

in the mean time, I wiggled the wires at idle and 3000 rpm and didn't get any changes in meter readings, or engine behavior.

 

at idle, there is a .7V drop between the 2 meters: 1 at RR connector (one lead on black, one on red) and the battery. 1 meter across the battery. Battery may read 13.3 while RR plug reads 14.0. shut off the engine and both meters read the same.

[Neil86]

Your voltage readings are tested on the RR side of the plug, not the harness side?

[Razorback]

You might want to verify your ground point is good....ie test it vs the battery negative

for low resistance...or use the battery negative as the ground point in the test.

 

only 2.5 ohms from frame to neg batt post.

 

tested open several times on each white lead to ground.

 

When I plugged the stator back in and cranked it, rev'd it again, this time the voltage when UP on the dash guage.

Then very quickly, it wasn't as consistent, but I did determine it hits 14.8V at the RR plug between 1500-1800 rpm, then goes down again as the revs go above 1800 rpm.

[Razorback]

Your voltage readings are tested on the RR side of the plug, not the harness side?

 

same on either side, verified multiple times today.good connection through that connector at this point.

[Neil86]

The RR black vs the battery negative stays very low or creeps up as you increase RPM?

[Razorback]

Didn't try that today, but yesterday it bounced between 130-320 mV at constant speed. I'll go check it right quick.

 

 

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[Razorback]

The RR black vs the battery negative stays very low or creeps up as you increase RPM?

 

When i turned the key on i had .875V right away across that connection. When i cranked it, it dropped to around 300mV.

 

if i slowly bring up the rpms, the voltage will increase to a full 1 V, as i bring the throttle a little higher, it will lower, but as i decrease from there, it may spike closer to 2V on the way back down ( i saw that a couple times).

 

I get .8 - 1.1 V at around 1200-1400 rpm.

 

When i kill it with the key, it drops back pretty low. turn it back on, back to .8-something volts.

 

what does it mean???

[Neil86]

and all the grounds were cleaned at some point.

[Razorback]

I'm still scratching my head on that one.

 

 

.

 

per the manual, it says the battery fluid level is low, but my sensor isn't hooked up, so that icon can be ignored until i do the mod for that.

[Razorback]

and all the grounds were cleaned at some point.

 

 

All that I can find. Right side of engine by water pump and smaller wire off neg batt cable goes to coils bracket. I removed that one and even scratched all the paint off the connection point and put it back on.

I cleaned the contacts on the disconnect on that smaller black wire that is about 6" from the battery.

I'll take another peek at that one in the morning just to make sure.

 

 

 

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[Razorback]

I've heard there is an instrument cluster ground, but I haven't found it yet.

 

 

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[Flyinfool]

When i turned the key on i had .875V right away across that connection. When i cranked it, it dropped to around 300mV.

 

if i slowly bring up the rpms, the voltage will increase to a full 1 V, as i bring the throttle a little higher, it will lower, but as i decrease from there, it may spike closer to 2V on the way back down ( i saw that a couple times).

 

I get .8 - 1.1 V at around 1200-1400 rpm.

 

When i kill it with the key, it drops back pretty low. turn it back on, back to .8-something volts.

 

what does it mean???

It means you have a bad connection on the negative side, between the RR connector and battery negative. The voltage that you are measuring is the resistance of that bad connection. The reason it goes up as the rpm goes up is that the ignition draws more power as the rpm goes up. As the amp draw goes up the the voltage drop also goes up. As that voltage drop gets bigger the dash and battery volt meters will go down.

 

You need to track down that bad connection. Follow the black wire from the rr all the way to the battery negative. clean every connection. inspect every place where a wire is crimped to a contact. The contacts may be clean but the crimp attaching the contact to the wire may be the bad connection.

[Razorback]

Will do.

 

 

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[frankd]

To verify that a bad connection at the ground wires is your only problem, I would take a 16-18 gauge (or heavier) jumper and connect it between the battery negative and the RR regulator black leads. Then start the bike and see if it's a bit better. It may not cure the problem completely because of the voltage drop across the jumper, but it should help.

[Flyinfool]

I kind of saved this test for last as it does put the electrical system under stress.

 

Shopping trip........

You can use a battery load tester to help find your bad connection.

 

Connect the load tester across the battery. When you push the button on the tester it will put a 100 amp load on the electrical system.

Bike should be running at a fast idle, maybe around 3000 rpm.

Connect your volt meter to both sides of the connection that you are testing.

Push the button on the load tester, if the connection is bad you will see a voltage on your test meter. If the voltage across that connection stays near zero, then that is a good connection.

 

You should only have to press the button on the tester for 1 or 2 seconds to determine if your connection is good or not. DO NOT get to crazy fast with repeatedly pushing that button or hold it for a long time. Everything needs time to cool down between tests. Pay attention to the temperatures of the tester, the battery, the RR and the wires that run from the RR to the battery. There is a very good chance that the bad connection could get real hot real fast, keep an eye out for that so you do not melt the connector that houses the bad connection.