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Discussion Starter #1 (Edited)
After being stranded twice last week with a dead battery and getting to practice my roll starts, I tested the electrical system this morning.... I followed the guides I found here, and these are my results using a digital multimeter, and having charged the battery outside the bike overnight until it read around 13.0v installed before starting the bike...

Here's my results:



Then I checked the voltage and continuity on the stator leads at 4000 RPMs...



It seems like the charging system is okay, even though I'd like the voltages to be above 14v... does this mean I should replace the R/R?

I guess I'm leaning towards a battery that won't hold charge, or something is draining the battery, or possibly the headlight relay is using too much juice...

If anyone is available to give me a quick phone call to help me figure this out, I'd really appreciate it... trying to get this fixed today... 678-577-7606

Some more photos... :)




I'm gonna cut those ugly bullet connectors off and solder the wires back together!

Thanks!!
 

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Sparky!!!
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looking at those stats the stator VAC is too low on lead A1, A2 is ify, and lead 3 is right on the money. What is the resistance between Stator A1 to engine case ground and Stator A2 to engine case ground? Warm? Cold?
 

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Discussion Starter #3
All the leads to engine ground were infinity warm and cold...
 

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I don't think those AC volts are that bad, 6v between highest and lowest. All well above 50v each.

I wouldn't replace a regulator without also testing it first.
 

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your DC measurements, where they using both leads at the battery? or was your neg lead on a chassis ground?

reason I ask, if you have a crappy ground from battery to chassis, you will get bad readings at the battery if you have both leads there. Voltage drop on the battery ground can be significant (and is part of systems total voltage) if its crappy/dirty
 

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Discussion Starter #7 (Edited)
Slimvulcanrider, they were all OL...

teddy, I did the DC tests on both the battery leads like I show in the photo... should I do them again between positive battery and engine ground?

I agree Spockster... the manual says the alternator output is between 50-70vac, so I didn't feel like it was out of that range, and they were all pretty close to each other... plus, a rectifier should be able to normalize to 14-15v dc (according to manual, that's the charging system output range) with that amount of input... but I didn't see anything over 13.5v dc at the battery terminals even at 4000 rpms... with the headlight off!

Oh, and when I say headlight off, I pulled the headlight fuse from the junction box...
 

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with the neg lead on engine or chassis ground, positive on battery, you will get the TOTAL output of the stator/reg.

if its much more than a couple 1/10ths of a volt difference between them, you have bad connections somewhere, either grounds, ground cables, or in the output wiring of the reg
 

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Discussion Starter #9
Thanks FoolAmI for your generosity! He mailed me his r/r unit from his bike so I could test it out for a few days... It seems to be working better than mine, so it seems my r/r is not working properly... I ordered a new Shindengen FH020AA MOFSET R/R kit from ebay, and hopefully it'll be here soon...
 

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Discussion Starter #11 (Edited)
Lol, well not sure it's figured out... I rode yesterday with FoolIAm's R/R, and seeing the same behavior... it's not charging the new battery either... I'm wondering if maybe some wiring, or something in the junction box might be causing this? I guess with the new MOFSET R/R kit, I'm going to bypass all the factory wiring and go straight to the battery, so maybe that's the solution?
 

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FYI: one of the leads to the stock R/R is a feedback loop to let the R/R compare battery voltage to regulator output.
This is what tells the system how much voltage to send to the battery.

It is possible that the feedback wire is not making a good connection I suppose.....might be worth a look.
 

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Discussion Starter #13 (Edited)
Okay, I just installed the new MOSFET kit this morning... and it doesn't seem to be doing any better than the old one... :(

I installed everything like the instructions said, and included a jumper lead from one of the stator wires to the yellow wire in the junction box harness to trigger the headlight... but still only getting 12.2V at idle... what does that mean??

I didn't use any of the wires from the stock harness... just cut the stator wires before the harness, and wired them directly to the one side of the MOSFET... Wired the positive output lead to the 30A fuse, and then to the positive battery terminal, and the negative output lead wired to the frame ground bolt where the stock negative battery cable is attached.

Do I need to use any of the other wires in the stock harness? Kc2, you mentioned a reference lead... does that have to be hooked up to a MOSFET type R/R? I was under the impression it didn't need that...

I really hope y'all aren't going to say its my stator after all... ugh!

Oh, and after looking at some other folk's posts and pics on here... it looks like I might have done the headlight relay wire a little different... I used another 12 gauge wire, crimped and soldered into one of the stator "pins" in the MOSFET input plug, and "jumpered" that over and soldered it into the yellow wire's pin in the junction box plug. The yellow wire is still where it was, I just soldered an additional wire between the stator pin and that pin... would that cause any issues?

Thanks,
 

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Chasin' the blacktop
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The numbers you had posted earlier from your stator sounded fine so I doubt it's the stator. Keep my R/R until Monday and fiddle around with the wires a bit more, check your grounds. Often it's something small like a dirty ground connection or a pin not getting a good connection.
 

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Sparky!!!
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actually like I said earlier, I don't like the A1 Stator output lead.. its way too low compared to the other two leads. Your initial post shows a good R/R and bad stator, like I had said earlier.
 

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I don't claim to be an expert on the electrical side but his voltage per lead and ohm #'s were in spec. True,,,, one lead was lower than average but still in spec.
 

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You might try the headlight trigger wire bypass and see if the DC volts change. Blue wire moved to the only empty hole on the connector, I forget which connector. (or simply disconnect the yellow for a test)

The brown reference wire isn't used with the MOSFET.

My ground goes straight from R/R to the battery, but yours should be fine if it's clean and tight.

The junction box can have problems with loose spade connectors in the plugs. I pinched mine to fit tighter, had to unlock and slide each one out of the plug to do it. Had low voltage to the fan and this fixed it. Your yellow wire is still in the JB too, might be a problem in the JB dragging the charge volts down.

I would also retest on the stator. Mine tested good a few times at first, then failed with faults to ground and the AC volts fell below 20. My R/R tested bad from day one.
 

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Sparky!!!
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hey spock.. with a mofset type R/R you should always read 14.5 volts +- 0.5 volts. never ever should a MOFSET read under 14.00 no matter what kind of load is on the battery.
 

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Not sure about that, if something is pulling the volts down ... a short, bad battery, etc.

And there are old posts about the headlight bypass bringing voltage up, along with posts about wonky JBs, nobody disputed those.

Aside ... I know when my batt. cable was loose I got a solid 15v at all times on the road.
 

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Sparky!!!
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The whole Reason to install the MOFSET R/R is to get the charging voltage at a constant 14.0+ volts under all load conditions. Yes a dead short a crossed the battery will bring down voltage, but would also fry the the JB, R/R and the CDI. The old posts you read about the headlight bypass are for stock R/Rs and for a temporary fix for the faulty headlight relay inside the JB.

If you read Post 13 BY the OP, you will see he installed the MOFSET R/R, which by the way Glory, you still didn't get back to me on the model number you used so I could calculate that in to your equation.

Since voltage is still low with the MOFSET R/R there are only two other possibilities, Stator and Battery... Battery tests out good in Post #1, but the stator still shows bad in the same post. I like all of his original R/R readings, I how ever do not like the A1 Voltage reading. with A2 and A3 reading almost 70 VAC, A 1 needs to read closer to 70 than 60. even though its reading in the 60-70 VAC range, with both A2 and A3 reading almost 70 and A1 is reading 62, that shows something is happening in the A1 Winding. I have a lot of experience working on 3 phase generators (which is exactly what our stator is) and have seen this same situation over and over again. I have even had other Vulcan owners call me with the exact same problem Glory is saying, and every one else on here had been saying its the R/R and the battery and it could defiantly not be the stator, and finally out of despair they change out the stator like I had been saying from the get go and presto the system is charging again.

One thing to look at first Glory, Is your frame to engine ground tight? The cable going from behind the right side cover to the transmission (10mm bolts on both ends)
 
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