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Thats 'Mr' Jr Member
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249 Posts
Discussion Starter #1 (Edited)
(Sorry for the long read)
My 2005 VK750 has left me stuck for the second time, on the other hand, at least now I know for sure that this bike is not charging the battery. I had this issue a month ago, recharged the battery and reinstalled it. I then started the bike with a test meter on the battery terminals and was getting 14 volts at 3K rpm. I also set up a Solar Trickle-Charger and thought everything was ok but yesterday I was out all day on the bike and noticed it getting progressively more sluggish each time I went to start it. I stopped at a gas station across from where I live to fill the tank and then it just would not crank. Got a jump from a friend and brought the bike home, removed the battery and put it on a charger to see it read 0% on the battery.
So although the voltage check at 3K rpm reads ok, it's just not charging. I can now see why installing an aftermarket voltmeter on these bikes is worthwhile. I have not unplugged the three bullet connectors to test the stator or done any of the tests on the R&R, though my mechanic recently installed a new headlight relay.
I am planning to give myself a new Vulcan Custom 900 for my birthday this summer but it is very hard on bikes down here in the Keys and was planning to keep this 2005 as my all-weather-daily commuter, being as I am less than ten minutes from my job and this old bike has already seen its share of weather. I am just frustrated with this charging issue.
Forgot to mention I bought this battery in December 2016 so it is not old.
 

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FREEBIRDS MC CENTRAL NY
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16,093 Posts
how old is the battery and is it a wet cell or an AGM?these bikes don't like wet cell batteries

Sent from my LGL34C using Tapatalk
 

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Thats 'Mr' Jr Member
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249 Posts
Discussion Starter #3
It's an AGM, only three months old.
 

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FREEBIRDS MC CENTRAL NY
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16,093 Posts
14 volts is enough to charge.sounds like your r&r is on the way out. mine did that once before the r&r died.voltage output varied on it.

Sent from my LGL34C using Tapatalk
 

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Alpha Geek
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487 Posts
14 volts DC output from the R/R is more than enough to charge. Did you mean on the stator phases before the R/R?

Did you test each leg of the stator to ground, and the voltage between each pair (AB, BC, AC) with the meter set to AC not DC? It should read something more like 40-70 volts AC because this is before it's rectified.

Going to the MOSFET R/R will greatly help charging, especially at idle. Well worth it, but don't bother with the expensive kits. You can buy the plugs separately on ebay for a fraction of the cost.
 

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Expert Novice
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14 Posts
I can relate , same year bike and everything. Test stator, rr and battery per manual . If you need pics of pages I can probably post them. The only difference is my bike has no gadgets wired in. May consider parasitic drains as well considering.

A lot of people had success with tuxedo mod to replace stator if it proves to be faulty. Consider checking that out after you determine the problem.

Also popular to relocate the r/r to a more convenient spot if that is the issue.


FYI: I wasn't successful in doing the tuxedo mod and am currently converting my side cover back to oem. And replacing my rotor due to damage from installing the mod. Dosnt mean it's a bad idea , I just did it wrong somehow.

Good luck .

2 years ago when I was dealing with this everyday I would be more help. Now I'm focused on replacing the charging system entirely and rebuilding the bike correctly.
 

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Expert Novice
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14 Posts
Btw.

I wasted a few hundred bucks not replacing the stator and r/r at the same time once. Seems like one bad unit causes the other to fail. May not be true. I think if stator is bad, replace both. If r/r is bad maybe try to just replace R/r because stator work sucks on this bike.

And 14 at 3k Rpms seems ideal at the battery terminal . Makes me think you have some sort of drain from aftermarket gadgets or grounds.
 

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Thats 'Mr' Jr Member
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249 Posts
Discussion Starter #9
Thanks Guys. I really appreciate the input! Currently there are no add-on devices that can drain power from the battery when the bike is off. There is a 12vdc automotive type plug with a cover, which I have never used, (but never know when it could be useful). It was put on by the previous owner. I've connected a pigtail plug to the battery that sticks out from under the seat so I can plug in my solar trickle charger, which seems to do a good job of keeping the battery topped up if I am not using the bike every day, but that has built-in protection to prevent the battery from discharging through the panel or overcharging the battery.
I was going to get out there with my test meter today and check the stator but it's been raining all night and is still raining as I write this, (haven't heard any jets going over so I'm probably in for a slow night at work).
Trying to work on my bike is kind of a pain because I live in a gated, over fifty-five park that does not really allow motorcycles, even though there are a lot of residents that own bikes. All motorcycles have to be in the motorcycle parking behind the park office, near the entrance, and I am three blocks away so I always end up making multiple trips back and forth as I find I need something else. It's a pain but my landlord is a friend of the family so my lot rent, where I have my trailer, is well below the local average, (which is high) and I am five minutes from work so there is a financial advantage to staying here for the next four years, till I retire.
Anyway, from what I what I have been reading I am suspecting the R&R is where I am going to find my problem. The system was working fine when I bought this old bike and the first thing I did with it was a 950 mile round trip to New Port Richie and back just to visit an old friend. The bike performed great and I was glad I bought it. It's my first V-Twin, water cooled, shaft drive bike and I really like it so I need to straighten this issue out.
The bikes going in the shop for new fork seals and some other maintenance soon. My mechanic has three work stations with lifts and he is a one man shop so I was thinking of explaining my situation at the park and seeing if he would consider renting me a work station to do a few things with my own tools.
:nerd:
 
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