Voltage Voltage Brownout-Popping-Poor Idle .. Need Ideas - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 9 (permalink) Old 08-31-2016, 01:26 PM Thread Starter
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Question Voltage Voltage Brownout-Popping-Poor Idle .. Need Ideas

Need some ideas on where to go with this. I still need to test my stator and r/r.

Have on the bike: TPE stator, MOSFET R/R, Two-Wire mod, AGM battery... all about 2 years old except the wire mod.


Below is a quote from me in another current thread by mick.park with similar symptoms.

mick's thread: https://www.vn750.com/forum/19-electr...ml#post1123306

__________________________________________________ _________________________________

Part of my post there today:

I'm almost at a loss for ideas, as I now have a very similar problem, starting yesterday. It's the darkest charging brownout I've ever seen, around 12.5-13v hot/idling with the fan on. Once the fan shuts off, the voltage is 14-14.5v.

What actually tipped me off to a problem ... The engine suddenly began popping from one cylinder on decel, and sometimes popped back out of one carb on takeoff, with a poor idle. I naturally thought it was the carbs again, which I just cleaned. As soon as the voltage went back to normal, it ran and idled fine, with no popping/sneezing.

While checking on possible carb problems, I unplugged the front cyl. spark plugs and determined it was that cylinder doing the popping, but it was at least firing.

Just before deciding this was a voltage problem, I dumped 3.5oz of seafoam into the tank. Meanwhile the bike had cooled and voltage became normal, so it ran fine immediately on startup for that test drive and for the next 20 miles. Was ready to declare a seafoam miracle, because it seemed just having it in the tank cured the problem. As soon as I got into slower speeds and the fan kicked on, brownout to 13v again. Back up to 35+mph for a minute... 14.5v. Going to start a post of my own so I don't get too far afield here with my own headaches.

I've got some testing to do, but for now I'm thinking fan/fan relay/JB .. or I'm losing the stator or r/r. Maybe my battery is getting weak, the bike has been parked a lot this summer.

I'm all open for suggestions if the stator and r/r check out good, and will start testing ASAP. JB finally bit the dust? I thought I was immune to this dammit! (charging problems)

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf

Last edited by Spockster; 08-31-2016 at 01:28 PM.
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post #2 of 9 (permalink) Old 08-31-2016, 01:52 PM
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as I always start, check ALL the grounds.. a slightly crappy ground connection could heat up and cause issues.

we have even seen stuff like loose battery cables cause these issues, so dont overlook anything (I know you wont, your too on top of it for that).

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post #3 of 9 (permalink) Old 08-31-2016, 02:49 PM Thread Starter
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Quote:
Originally Posted by michiganteddybear View Post
as I always start, check ALL the grounds.. a slightly crappy ground connection could heat up and cause issues.

we have even seen stuff like loose battery cables cause these issues, so dont overlook anything (I know you wont, your too on top of it for that).
Heh, thanks for the confidence in me but some days I'm dumber than a box of hair. Oldtimer's and fluoride, I think. For about 15 miles, I really thought I had performed a seafoam miracle. Hey guys, all you have to do is show the bottle to your bike and it will straighten the eff out! lol

Will check grounds, always forget that! When my pos. cable got loose at the battery, the meter pegged at 15v. A nice pretty blue light.

Meanwhile, I caught this funny quote:

Quote:
Originally Posted by mick.park View Post
Maybe I'm missing something- do you guys take your Vulcans on long rides or are all of us just constantly in the garage playing with wires and stators forever?

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf
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post #4 of 9 (permalink) Old 08-31-2016, 03:08 PM
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Bummer. I guess not even the elite are immune from the electrical gremlins.

If the stator and r/r are good, they should be able to drive the fan even if the battery is weak, right? or would attempting to charge a weak battery pull enough amps from the electrical system that a fan coming on would break it's back?

If a short in the primary coil of the fan relay is the problem, you should be able to tell by pulling the JB 10-pin connector and checking for a short between pins 2 and 4 on the box. Anyone know what the 'working' resistance of the primary relay coil is? Could compare with pin 11 and 12 to see if there is a discrepancy between the fan relay and the starter relay.

I'm somewhat baffled by the relays' ability to cripple a bike without completely taking it out of commission. When I've seen things short elsewhere it blows a hole in the wiring where the short happened. These relay coils seem to short & stick together, but not badly enough to blow a fuse or melt wiring. Its just weird.

1992 US-nonCA * tuxedo mod * r/r relocated

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post #5 of 9 (permalink) Old 08-31-2016, 03:08 PM
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There is a reason I own other motorcycles. Love the Vulcan, but it is still finicky. It hasn't died on me in a long time, though.

1986 Kawasaki Vulcan 750
NGK Iridium Plugs #7803/DPR7EIX-9
Duralast Gold ETX15 AGM Battery
Coastered & Shaved
TOC MCCTs
Metzeler ME880 [110/90-19, 170/80-15]
Balance Dampers Replaced
Tuxedo Mod
Rebuilt Forks w/ Progressive Springs
V&H Cruzers
VN750.com Grill Cover
Meanstreak Seat
Emgo 23-92411 Handlebars
MOSFET FH012AA R/R


1990 Kawasaki Vulcan 750

1998 Honda VFR800 FI

2014 Honda VFR800F

1989 Pontiac Firebird Formula 350
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post #6 of 9 (permalink) Old 09-01-2016, 01:04 AM Thread Starter
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Thorn, I'll check those items. Fairly certain my start relay is toast in some form, my main reason for doing the 2-wire mod last year.

Didn't get a lot done today. Battery after sitting overnight was at 12.79v.

Started the engine, charge volts rose slowly to near normal, rpm was slow to come up while the choke was on, engine sounded ragged, had some light popping in the exhaust, revs were kind of sluggish at first (after the choke was off).

Got it on the road and warmed up, charge was good, ran good, revs fine, not ragged or popping. Never got to city traffic since it tried to rain after a short ride. Let it idle at the garage until the fan came on, volts dropped to 13.5v, still idled/revved ok, no popping.

Don't know what to think ... might need ridden more!

We get our miles on the eternal test rides!

BTW, when the volts were down yesterday, I was hearing the growl, hum, groan that other people have posted about coming from the stator cover area during low volt situations. Didn't hear it today.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf

Last edited by Spockster; 09-01-2016 at 01:12 AM.
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post #7 of 9 (permalink) Old 09-01-2016, 01:10 AM Thread Starter
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Something else I found....

Was poking with the meter on different grounds under the right side cover ... Got full battery voltage through all I checked, except the screws on the RLU, which only showed about 9 volts. Probably no biggie, just my only major discovery for now.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf
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post #8 of 9 (permalink) Old 10-19-2016, 01:21 AM
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I have a stupid question for you guys. What the hell is a brown out?

Don't worry!!, It's just a bump in the road.
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post #9 of 9 (permalink) Old 10-19-2016, 01:58 AM
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I'm not being a smart ass here,this is just an easy way to explain it.a brown out is basically half a black out.a voltage drop,but not a complete outage

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