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Discussion Starter #1
Fellas,
I am new to this group as well as a new Vulcan owner. I have a 1991 VULCAN 750. I finally got the bike running after cleaning the carbs and figuring out which hose goes where. the previous owner was trying to do the ear shave procedure so the surge tank is gone and I have air filters on the carbs. I ordered new jets as discussed on multiple forums in this site. once I got the bike running and able to turn the choke off I took her for a ride around my neighborhood for about 1 mile, after I returned to my house and went up the driveway the bike immediately shut off, as if I hit the kill switch(which I didn't). I have a neighbor who works on Harleys and isn't savie with these bike but he mentioned it could be a bad Stator or R/R. im going to do the tests today to check the battery and see if she is at the proper voltage and isn't being over charged from acceleration. I will be doing all repairs myself so if you have ideas on good products and prices for these items please send the link.
Any input would be amazing.
 

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Hey tirmboli, welcome.

So, if it were a charging issue, I would expect:
1. you would be able to go further than a mile on a fully charged battery.
2. when it died, it would probably sputter a bit as the spark got weaker before dying completely.

Checking the stator is not a bad idea generally, but I don't think it will be the culprit here. If it was in good condition previously (the old owner was doing an ear shave, so it was probably running as intended) then chances are super low that it got fried on a 1 mile test ride.

The wiring may have some corrosion in the connectors, or a broken wire somewhere. The kickstand switch can go bad, making it so the bike dies any time you have engine power being transferred to the wheels (clutch engaged and in gear). The ignition switch can go bad, making it seem like you turned the bike off. A loose ground wire or battery terminal can bugger everything.

What exactly happened when the bike died? What gear was it in? Was the clutch engaged or not? Were you turning hard in order to make it into your driveway? Did you put the kickstand down and it died? Did the lights stay on or turn off? Were you able to re-start the bike?
 

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Discussion Starter #3
Hey tirmboli, welcome.

So, if it were a charging issue, I would expect:
1. you would be able to go further than a mile on a fully charged battery.
2. when it died, it would probably sputter a bit as the spark got weaker before dying completely.

Checking the stator is not a bad idea generally, but I don't think it will be the culprit here. If it was in good condition previously (the old owner was doing an ear shave, so it was probably running as intended) then chances are super low that it got fried on a 1 mile test ride.

The wiring may have some corrosion in the connectors, or a broken wire somewhere. The kickstand switch can go bad, making it so the bike dies any time you have engine power being transferred to the wheels (clutch engaged and in gear). The ignition switch can go bad, making it seem like you turned the bike off. A loose ground wire or battery terminal can bugger everything.

What exactly happened when the bike died? What gear was it in? Was the clutch engaged or not? Were you turning hard in order to make it into your driveway? Did you put the kickstand down and it died? Did the lights stay on or turn off? Were you able to re-start the bike?
Thanks for the reply.
i took a video of it. It come in four one one minute clips.thia time i didn’t ride her I just let it run I side the garage. First she is idle at 1100-1400 rpms for a good minute with the voltage at around 13.10.the rest of the videos are of the voltage slowly dropping. I revved the engine a couple times to check the r/r to see if it’s doing it’s job and it seems like it was cus it didn’t rev over 14 maybe a tiny bit but it dropped back to 14volts. The bike got to around 12.25 in the video and the shut off.
 

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I would think anything over the standing battery voltage indicates that the bike is charging or at least trying to charge. Right before my stator died I had installed a voltmeter along with a set of running lights. At the time I didn’t know the stator was on the fritz, my voltage levels during a ride were dropping down to around 10.x. So for you to see 13.x or 14 is a good sign. Do you have a service manual? If so it outlines how to test the stator with the bike running and off.
But I think Thorn is probably on the right path of it being something else. The bike will run with a dead stator until the battery loses its juice.
 

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Just to set expectations, the vast majority of vn750s won't charge at idle RPMs, so they'll drain the battery slowly unless actually being ridden.
 

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Do all the tests.

Not sure anyone has a go-to for stators anymore. There's still some places rewinding them.

I swear by the MOSFET RR kit I put on mine, along with relocating it under the left side cover.

The kit I used is at roadstercycle.

Looks like this didn't post. Figured out I have to 'post reply' twice from my phone, so here's that post.

Excellent points from Thorn and mmart.
 

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Discussion Starter #7
Thanks guys,
Ill run the stator test when I get off work. I checked all the wires and grounds and cleaned them all up before I got the bike running so those are good. ill post results when I do the test.
 

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Discussion Starter #8
Ok so I did the testing on the stator. I did both static and dinamic.
phase1-2 readings At .6.
phase 2-3 readings at .7.
and phase1-3 readings at .6 ohms.
the I went from the starter case to test if it was 0L and it was weird. It would read OL then freak out to a random number on all three phases. I couldn’t get accurate reading on that one.
Dynamic read was good to I think it went from in the 20s to like 50s when I revved it during the test. Still unsure what to do about this. Not sure how to check all the wiring without taking the bike apart to check it. I less there is a way to test with the multimeter.
 

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Get the engine good and warm then redo the tests.
 

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Discussion Starter #10
Static
1-2: .5ohms
2-3: .6ohms
1-3: .7ohms
Can’t do dynamic due to bike dead again from warming it up.

this picture is me doing positive on the stator terminal and the negative on the case where the stator is located. I was getting high readings. I thought I’m supposed to get OL. But once again I’m new and not sure.

52174
 

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I’m not sure which connector that is. The stator if it’s stock set up has 3 yellow wires that have bullet connectors.
 

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Discussion Starter #12
I’m not sure which connector that is. The stator if it’s stock set up has 3 yellow wires that have bullet connectors.
it was connected to the r/r it has the three yellow wires on bottom where I was testing.
 

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Looks like the stator is grounded on that leg.

Could repeat the test farther toward the stator at the bullet connectors if they haven't been soldered. If it all checks good, hot and cold, then the wiring to that plug is grounded.

I don't follow what dynamic testing is.
 

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Discussion Starter #15
Dynamic is testing the AC volts with the bike running. at least thats what i go from Partzilla: how to test your stator.
 

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Ok thanks, don't think the manual calls it that. You can download it from my signature.

The bullet connectors are a known problem spot. If they're corroded, just cut them out and solder the wires.
 

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Discussion Starter #17
So I changed the stator and it seemed fine but once again I rode it and it died once I got back to my house. Changed the jets in the carb tried it again and nothing still. I let it idle for a while the second time and got on the bike and one I put her into first gear she died. Connections seem good I had a buddy do those and he’s good at it. Not sure why it keeps dying after a mile ride or idle for ten min.
 

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This is why we test stators when hot. Because they can work when cold, but fail after warmup.
 
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