BV 500 voltage regulator or alternator problem
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2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Fri Oct 08, 2010 10:09 pm quote
So my scooter battery wont keep a charge. I replaced the battery and it's good when I use my tender but it only take about 12 miles of riding and the scooter dies. Im a little afraid of buying a new voltage regulator seeing that it's close to $200. I have read this and that comments about checking some kind of hidden fuse. Anyone know where to find the hidden fuse on the bv 500 or have any idea on how to confirm a bad regulator?
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Sat Oct 09, 2010 12:45 am quote
I don't know the BV500 personally, but all 500cc Piaggio bikes I've had before have had a 30A fuse sheltered under the cover to the terminals of the starter relay - this fuse being just to protect the O/P of the regulator.

The terminals that grip this fuse can easily corrode, and there have been numerous cases on the MP3 500 (Fuoco) where they have disintegrated completely, and the heat build-up during this process has destroyed the fuse.

So *if* the BV500 has a similar configuration, that's the first place to look for your problem.
Member
2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Sat Oct 09, 2010 1:04 am quote
Where would I find this on the scoot?
So Im new to scooter repair and until two days ago had only ridden and never removed a panel. So I have no idea where to look for this magic fuse. So far I can't find any decent pics or anything to point me in the right direction. Do you or anyone else know where I can find this magic fuse?

The terminals that grip this fuse can easily corrode, and there have been numerous cases on the MP3 500 (Fuoco) where they have disintegrated completely, and the heat build-up during this process has destroyed the fuse.

So *if* the BV500 has a similar configuration, that's the first place to look for your problem.[/quote]
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Sat Oct 09, 2010 1:07 am quote
Follow the thick red cable from the battery - the first thing they connect to should be the starter relay and the 'hidden fuse'.
Member
2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Sat Oct 09, 2010 1:11 am quote
Ill post when I find this thing.
Ive been a car guy my whole life but this scooter stuff is great! I simply with I had smaller hands to get in under and around things. Hmmm I guess I should wake up the three year old at 2am to help with scooter repairs. Thanks for the tip Im going fuse hunting.
Ossessionato
Joined: 27 Jun 2008
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Sat Oct 09, 2010 3:36 am quote
Also, use a voltmeter and check the voltage at the battery. At idle, it should be in the neighborhood of 12.7 volts. Then check it with the engine revved: it should not exceed 14.8 volts. If it goes up to 16 volts or above when revved, you have a bad voltage regulator. I used to own a BV500 and mine went bad. The symptom that I had was the "check engine" light would come on when I accelerated and go out when I went back to idle. The voltage regulator is located under the rear fender and it takes around two hours to disassemble, replace the VR and reassemble all the plastic panels.
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2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Sat Oct 09, 2010 9:58 am quote
My voltage goes down not up
So if the regulator issue causes the voltage to go up then what would cause the voltage to go down? The alternator is my first thought but it seems to test fine. Any other thoughts other then this hidden 30amp fuse that I can't seem to find?
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Sat Oct 09, 2010 10:06 am quote
Re: My voltage goes down not up
andrewman wrote:
So if the regulator issue causes the voltage to go up then what would cause the voltage to go down? The alternator is my first thought but it seems to test fine. Any other thoughts other then this hidden 30amp fuse that I can't seem to find?
It's overcharging the battery so the plates in the battery have sulfated........ergo, the battery will charge but it won't hold the charge because the battery is fried.
Member
2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Sat Oct 09, 2010 10:13 am quote
I just replaced the battery
So as son as i had the prob i replaced the battery and tested the system after about a 15 min ute rid and that was the voltage. I doubt it killed the battery in 15 minutes of driving. Im really starting to think the alternator may be the issue. I have check it and it seemed fine. It's odd how confusing it is to track down the problem on such a simple motor. If I do need to get parts where can I find them at a price thats not going to break the bank.
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Sat Oct 09, 2010 10:18 am quote
Did you test the voltage at the battery (at idle and being revved)? You say you tested it but you didn't post the results. The answer will be with the results of that simple test.
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MP3 500
Joined: 20 Aug 2008
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Location: Ashburn, Va
Sat Oct 09, 2010 10:27 am quote
Re: My voltage goes down not up
andrewman wrote:
So if the regulator issue causes the voltage to go up then what would cause the voltage to go down? The alternator is my first thought but it seems to test fine. Any other thoughts other then this hidden 30amp fuse that I can't seem to find?
Did you pull the cover off the relay? The fuse is under the relay cover.
Member
2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Sat Oct 09, 2010 10:37 am quote
voltage drops to 11.2
XLR8 wrote:
Did you test the voltage at the battery (at idle and being revved)? You say you tested it but you didn't post the results. The answer will be with the results of that simple test.
It was 12.4 before I started it and after 3 minutes of running and revved to about 3500 the voltage was 11.2
Member
2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Sat Oct 09, 2010 10:38 am quote
Re: My voltage goes down not up
Did you pull the cover off the relay? The fuse is under the relay cover.[/quote]

Where is the relay that holds the 30 amp fuse? I have taken the whole rear end apart and cant find it. Im just not exactly sure what Im looking for other then some random pics I have found in other posts.
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MP3 500
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Sat Oct 09, 2010 10:41 am quote
Follow the positive cable from the battery and it will lead you right to it.
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Sat Oct 09, 2010 11:08 am quote
Re: voltage drops to 11.2
andrewman wrote:
XLR8 wrote:
Did you test the voltage at the battery (at idle and being revved)? You say you tested it but you didn't post the results. The answer will be with the results of that simple test.
It was 12.4 before I started it and after 3 minutes of running and revved to about 3500 the voltage was 11.2
Must be either the fuse or a bad alternator. It's not the VR.
Member
2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Sat Oct 09, 2010 11:45 am quote
thanks for the info XLR8
Im trying to track my cable to find the hidden fuse. I just got all the body apart but must put the project on hold until later today. Will post what I find and pics of where this is located for future use as others have this prob. Thanks guys.
Member
2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Sat Oct 09, 2010 12:40 pm quote
found the fuse and its fine.
The hidden 30 amp fuse on a 2007 piaggio bv 500 is on the right side of the scooter about 10 inches forward from the battery. So the voltage regulator is fine and the hidden fuse is fine. So is the only other possibility the alternator?

photo.JPG

Member
2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Sat Oct 09, 2010 2:24 pm quote
Hidden fuse Piaggion BV 500
this is located about ten inches forward of the battery on the right side of the scooter. You will need to remove the full side panel to access this point.

hiddenfuse.jpg

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Sat Oct 09, 2010 2:33 pm quote
At this point, I think it's the alternator.
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Sat Oct 09, 2010 2:41 pm quote
Have you checked continuity through the hidden fuse? The fuse itself may be fine - the mis-matched metal connectors may not be. And don't confuse the *spare* 30A fuse with the one that does the work.
Member
2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Sat Oct 09, 2010 4:53 pm quote
What would be the best way to check the flow of electricity through this circuit? Also Im pretty sure you were joking about the spare fuse but at this point I simply feel lost.
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Sat Oct 09, 2010 5:03 pm quote
I'm not joking about the spare fuse - if there isn't one there the original owner has already used it...
Member
2007 Piaggio BV 500
Joined: 08 Oct 2010
Posts: 15
Location: Monterey Ca
Tue Oct 12, 2010 4:18 pm quote
So has anyone replaced the generator?
So has anyone replaced the generator on a bv 500? Also where is a good place for parts? My local shops seems to want a lot for suck a simple part. Pretty much any input would be helpful.
Member
Piaggio BV500
Joined: 16 Oct 2010
Posts: 8
Location: Santa Rosa, California
Tue Nov 30, 2010 4:00 pm quote
I'm having problems as well.
I have used this thread to try and diagnose my BV500, which is having similar problems. I'll post a brief history.

Back in July, I rode to the USGP and camped all weekend at the track with my scoot. Upon attempting to leave the track after the race, my bike would not start. I pushed it down the hill and had a car battery jump it. I rode for as long as I could from the track in order to keep juice flowing back into the battery. I had to stop for gas once in order to make it home, and did it so after about 2 hours. When I tried to start it to leave the gas station, it was dead again. This is when I discovered the positive lead had rattled loose. I got towed home and fixed it with a new battery and loctite on the terminals. Cool.

Now, in November, my new sealed battery from the summer is also dead, but the lead being loose is not the cause. Something is frying my batteries or keeping them from charging at all.

I did the voltage test and found a 12.6 at idle after some deep charging, and around mid 14's while revving. This makes me think that the regulator is doing its job.

I just tore down some plastics and found that the 30A fuse is also okay, and the spare has not been used.

My bike also displays the symptom of the check engine light on while in motion, but not at idle, and has since I purchased it used.

Is my alternator bad? I want to try the running voltage test again in order to verify those numbers, and its deep charging now for one final hurrah.

Any ideas?
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Tue Nov 30, 2010 5:29 pm quote
The 30A fuse can appear fine - but the connections to it and then to the battery lead can be iffy. However the voltage checks would indicate all is well there.

So maybe a dodgy connection to the frame?
Molto Verboso
BV200, P200E (2),V90 and now a Big Ruckus
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Tue Nov 30, 2010 5:51 pm quote
Recently, I thought I had a bad charging system on my BV and it was not the case at all. Turns out I overkilled the battery by running the fan manually too much (thermal switch is bad) I bought a new battery and the same thing happened. I tested the charging system and it was fine. I learned that a motorcycle battery that is overly discharged may not take a charge at all and may be tricked into charging. It took 4 times to trick this new battery into taking a charge with the trickle charger. Once it was charged and I regulated how much I use the fan, the problem was over.
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Tue Nov 30, 2010 7:42 pm quote
'Kin 'Ell - why not replace the thermal switch and have the system operate as designed? Far less aggro...
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Piaggio BV500
Joined: 16 Oct 2010
Posts: 8
Location: Santa Rosa, California
Tue Nov 30, 2010 9:50 pm quote
Well, I ran the voltage test again with different results. I'll try to make this as clear as possible.

I'm sure the battery has been abused from all this up and down charging and draining, so it tested at about 10.8V before hitting the charger. I charged it at 12V6A until it was reading about 14.5V while attached to the scoot leads and ready to rock.

I pulled the charger off of the bike and batter, and it reluctantly turned over. Now it was just the bike idling under its own juice, no charger attached.

It read about 14 at idle after coming off a hefty charge. Upon revving, it revved to about 17.5V. This makes me think the regulator is not regulating. Is this the case? Or is everything reading high after coming off the charger? I figured it doesn't really matter if the battery is juiced high, it should still regulate things. Is it possible to have a bad regulator and still have a good 30A fuse?
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Wed Dec 01, 2010 11:40 am quote
17.5V? Your regulator is toast I'm afraid. Replace ASAP.
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Wed Dec 01, 2010 12:01 pm quote
andrewman if this is not repaired yet (not charging)
you might want to follow your main harness from your altenator towards your battery, I had the same issue on an X9500 and I found that a wire had worn itself raw on part of the frame and melted into another wire, I ran my hand along the harness and felt the tape had hardened where it had overheated opened it up . A couple of dollars and a few terminals later it was fixed, also there is a connector along the same harness just before you get to the battery that has given some grief in the same fashion, (overheating and melting) in the early years of the 500.
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Piaggio BV500
Joined: 16 Oct 2010
Posts: 8
Location: Santa Rosa, California
Wed Dec 01, 2010 1:20 pm quote
Thanks for the feedback. I'm pretty convinced that its the VR as well at this point, and will replace it. I'll do a check of the harness as well. Good times.
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Wed Dec 01, 2010 1:42 pm quote
muchacho_pat wrote:
Thanks for the feedback. I'm pretty convinced that its the VR as well at this point, and will replace it. I'll do a check of the harness as well. Good times.
I agree that it's the VR (and the battery may also be toasted).
Member
Piaggio BV500
Joined: 16 Oct 2010
Posts: 8
Location: Santa Rosa, California
Wed Dec 01, 2010 5:56 pm quote
XLR8 wrote:
I agree that it's the VR (and the battery may also be toasted).
Yeah its done. I'm glad to solve the problem this time and not waste yet another battery with overcharging. Time to find a VR. Has anyone used the supposed Honda VR that may work for this bike?
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Wed Dec 01, 2010 6:09 pm quote
Honda ones peg out as readily as the OEM Ducati ones - the standard one is fine, especially if you can find some way of keeping it cooler.
Member
Piaggio BV500
Joined: 16 Oct 2010
Posts: 8
Location: Santa Rosa, California
Thu Dec 02, 2010 7:08 pm quote
jimc wrote:
Honda ones peg out as readily as the OEM Ducati ones - the standard one is fine, especially if you can find some way of keeping it cooler.
Well i just discovered its location up under the seat bucket. I'm wondering if I fried it when I took jumps from cars during the summer. Anyways, time to bite the bullet, order a new one, and think about increasing cooling. Thanks again for the help, I just discovered this forum as a resource.
Hooked
BV500
Joined: 02 Oct 2007
Posts: 106
Location: NY NY
Thu Dec 02, 2010 9:46 pm quote
jimc wrote:
17.5V? Your regulator is toast I'm afraid. Replace ASAP.
I 2nd that. Had the same problem with my BV500 few months back. Apparently this is a common problem with Master engines. If you don't wanna pay the astronomical $200 + price to get a new one from the dealer check out Italian Ebay. Got mine for $50
Member
Piaggio BV500
Joined: 16 Oct 2010
Posts: 8
Location: Santa Rosa, California
Thu Dec 09, 2010 8:13 pm quote
It is done
Well, I just finished switching in a new voltage regulator and battery. Runs fine, passes the voltage test, and seems to have lost the engine light while running issue as some had described above. Thanks for all the advice. I'm glad I did it myself.
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