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booyakasha!
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Discussion Starter #1
Just wanted to give everyone a bit of interesting info regarding voltage rectifier-regulator parts.

I'm currently my second voltage rectifier-regulator installed at the dealer and both were covered under warranty.

SoCal Ducati informs me that voltage rectifier-regulator part number has rolled over to a different one. Speculation is that this one is possibly more reliable/better.

Old P/N: 540.4.010.1A
New P/N: 540.4.011.1C

The old P/N was very, very common across other models:
all SportClassics/GT
2006-07 S2R/S4R Monster
2005-09 Multistrada
2008 Monster 695
2002 Monster 400
2005 Supersport 800 & 1000
and possibly many others (excluding the Superbikes 848/998/999/1098/1198)

The new part is common to:
ST2, ST3, and ST4
MH900e
748 and 996
SS 750ie and 900ie
and possibly other more.

It seems like the (ironically) older part number that is better than the newer one.

Now we know that it's interchangeable.

Let's hope it works. :think:
 

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booyakasha!
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916 Posts
Discussion Starter #3
Why did it fail and what yr is your bike? Oh what were the symptoms?
I don't know why it failed. There's nothing about the bike that is making it fail. The dealer mentions that a bad batch of regulators/rectifiers (or low quality) out in the market. It is the original part for the SportClassics (P/N 540.4.010.1A). That's why they are using the other part number (540.4.011.1C).

Bike is a 2007 SportClassic 1000S.

My symptoms are typical of a failing regulator/rectifier that can be found here by searching for "voltage regulator".

Bike seems to "lose" power, runs rough, and then stalls. When you try to start it, all you hear is a "click" and it it will not start. Essentially, the regulator/rectifier failed and you were running on battery until it ran out of juice.

So I guess DNA is telling the dealers to use P/N 540.4.011.1C on the SportClassics.
 

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unM0derator
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2,853 Posts
I haven't had this issue happen to me yet, but I have talked with parts managers about Ducati's love for changing part numbers.

It can be something as simple as the old lot was exhausted, and they got a new lot, but the number in the computer was obsoleted, requiring the new lot to have its own part number.

There doesn't seem to be much rhyme or reason for Ducati's part numbering scheme.

.02
 

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217 Posts
Well, it looks like my R/R has gone bad too on my PSle. Went to hop on my bike and the the bike just clicked. It didn't even turn over. So I just plugged my battery charger in and charged it up. After several hours of charging the bike started right up. I didn't ride it, but the next day it started right up so I decided to run a few errands. On my way home, it just barely turned over enough to start.
A new battery was put in last October because of faulty terminals in the battery so it probably not a bad battery. I'm gonna get a voltmeter this weekend and make sure that its my R/R before I order a new one.
I'm thinking of ordering one of these:
http://www.electrexworld.co.uk/rr53-regulator-rectifier-regulator-rectifier-ducati-honda-vfr800-996-748s-electrical-parts-for-motorcycles-electrex-world-749-0.html
.....or should I go to the Ducati shop and get one.
BTW, It looks like I'll be relocating it too.
I also looked at my current R/R for part numbers and didn't find anything like you describe.

Thanks for any info and or advice,

Mike
 

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booyakasha!
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916 Posts
Discussion Starter #6
Well, it looks like my R/R has gone bad too on my PSle. Went to hop on my bike and the the bike just clicked. It didn't even turn over. So I just plugged my battery charger in and charged it up. After several hours of charging the bike started right up. I didn't ride it, but the next day it started right up so I decided to run a few errands. On my way home, it just barely turned over enough to start.
A new battery was put in last October because of faulty terminals in the battery so it probably not a bad battery. I'm gonna get a voltmeter this weekend and make sure that its my R/R before I order a new one.
I'm thinking of ordering one of these:
http://www.electrexworld.co.uk/rr53-regulator-rectifier-regulator-rectifier-ducati-honda-vfr800-996-748s-electrical-parts-for-motorcycles-electrex-world-749-0.html
.....or should I go to the Ducati shop and get one.
BTW, It looks like I'll be relocating it too.
I also looked at my current R/R for part numbers and didn't find anything like you describe.

Thanks for any info and or advice,

Mike
I was also looking at that Electrix, too. Read good things about it but all the effort and money would be wasted unless it gets relocated.

I just looked up the PSLE's R/R on www.Ducati.com and the Spare Parts catalog shows "540.4.010.1A Voltage rectifier".
 

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592 Posts
I haven't had any problems with regulators (at least not Ducati ones, Hondas are a different tale), however I have seen a few guys who have mounted PC cooling fans onto theirs which seems to alleviate the problems caused by the reg/rec sitting in a pool of still air. These are cheap 12v fans that are easily wired in and small and light enough to fit into small spaces easily.
A bit less drastic than drilling holes everywhere.:think:
 

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Old Wizard
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3,000 Posts
Relocated Regulator

Relocating it to the tail is a better alternative for cooling. PC-type fans don't work well. Tried it.

 

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booyakasha!
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Discussion Starter #10
I was thinking of mounting it under the tray but I was afraid that dirt and the occasional splash of water might ruin it.

Shazzam, how does it hold up?
 

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My voltage regulator/rectifier is definately fried. I charged the battery and check it with voltmeter. Battery is good and holding a charge. Started the bike, revved to 3000 rpm and checked with voltmeter. Should be around 14.5 +/- .5. I was at 12.2 according to another informative thread I read about the regulator/rectifier.

Went for a quick ride around the block (cause I hadn't ridden it in a week and had to atleast ride it while I had some juice left) and checked the battery again, it was at 11.8 volts. The regulator/recitfier was also soo hot it burned my finger.

Now to get me up and riding again I searched locally at CL and Ebay before orderin an Electrex unit as I hate waiting for packages. The electrex unit from their website states that its the same unit for the 749 and a bunch of other ducati's. When I checked the part numbers on ducati website the're different numbers (749 vs paul smart) 540.4.019.1A and 540.4.010.1A. If the electrex unit compatible for all the bikes listed does anyone know if the ducati regulator/rectifiers are compatible even though they have a different part number?

BTW aeolian, looks like a great idea. Might be a good solution as opposed to moving the unit out and more exposed.
 

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Old Wizard
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3,000 Posts
There are two parts to this problem.

The first part is that Ducati charging systems have stator wires that are seriously undersized and they overheat. In particular, the in-line connector develops a high resistance from being either too loose or from corrosion, and they heat-up and melt the plastic connector and damage the wire's insulation.

The rule-of-thumb for sizing wiring is that if it needs to carry 20 amps use 12 gauge wire; 30 amps needs 10 gauge; 40 amps needs #8 gauge. Early bikes have 350 watt/29 amp two-wire charging systems so 10 gauge should be used.

1999 (and later) three-wire 500 watt alternators produce a little over 40 amps. So you ought to replace the wiring all the way back to the stator with 8 gauge wire.

These wires have to pass high amperage continuously. There’s an electrical phenomenon called I-squared-R loss. That is, if you run 30 amps through a corroded or loose connector having (say) a 1/2-ohm resistance, the heating effect is 30 X 30 X 1/2, or 450 watts. That’s a lot of continuous heat. This heat just conducts down the wire, cooking the insulation as it goes.

Just like you can’t put your hand on a 450 watt light bulb while it’s lit, you can’t expect a plastic connector to survive radiating 450 watts of power either. A corroded or loose connector always has a higher resistance than the adjacent wires and it will heat up enough to melt connector plastic parts and nearby wire insulation. That’s why it’s best to solder the wires directly together and eliminate connectors entirely.

It is the connectors heating up that causing the insulation and conductors to melt and short out. Even if you haven't had a charging failure, next time you have a chance, check your wiring for damage.

On my 916, for example, the stator wires got so hot that the insulation became brittle and cracked near the regulator connectors. A closer examination showed that the damage extended along the wire all the way back to the engine casing. I could scrape off the softened insulation with my fingernail.

So even if the stator wire resistance measurement and the voltage output checks out OK, the output to the regulator is unreliable because the insulation between wires (that run in a common sheath) breaks down at the higher voltage levels at higher RPM. At the very least, remove the sheath and separate the wires.

The stator wires generate the highest heat load at the points of highest resistance on both ends; where they attach to the stator and at the connector to the regulator/rectifier.






So rewire it with 8 gauge wire and eliminate the regulator connector plug.


The second part of the problem involves inadequate cooling of the regulator/rectifier (RR) itself. If the RR overheats it fails.

First a little background. In 1995, after having to replace a slew of 916 RR's under warranty, Ducati made some modifications to their RR and sent them out as replacements. The new versions were marked with a dot of green paint to distinguish them from the older version.

However, RR's continued to fail at a high rate so Ducati redesigned it for 1998. The major improvement was the addition of a large aluminum heat sink to dissipate heat. RR's put out a lot of heat themselves and have integral cooling fins built into their casing to help reject this heat. The additional heat sink, although not finned, was however somewhat reflective and designed large enough to shield the RR from the direct heat from the front cylinder exhaust pipe.

Early Ducati 916/748 alternators are rated at 300 - 350 watts (25 - 28 amps) output. For 1999, Ducati redesigned the electrical system for a larger capacity by going from the 350 watt single-phase design to a 500 W three-phase system. Three-phase alternators have three wires coming out of them. They produce an AC output that has a higher frequency than a two-phase design so the RR presumably has to do less work conditioning the waveform and converting it to DC. The new alternator has additional wattage available to run the lights, fuel pump, ECU and accessories but the higher output still has to pass through the regulator.

The 2001 bikes also have a redesigned fairing with a bigger NACA duct to direct cooling air to the RR. The problem is that it still gets cooked at stoplights from its own heat and the nearby front cylinder exhaust header because there is poor cooling air circulation in the lower fairing. If you watch a voltmeter across the battery under these conditions you'll see the battery drop into a discharge condition. Sometimes the RR will recover after cooling down, but eventually fail.

Some of the newer bikes have a revised fairing design with openings on the upper surface that may help somewhat in the convection cooling of the RR.

The best solution is to move the RR outside the fairing to the outside air stream for better cooling.

In my case, I replaced my fifth failed regulator with an Electrex unit, extended the larger gauge wiring (see above) and mounted it on the underside of the license plate holder facing the rear tire where it’s hardly noticeable.
 

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I don't know if I should be flattered or offended! Thanks though :)

After reading all this I'll be checking the bike when I get it back and maybe relocate it by the oil cooler.


I got the bike back Friday and the first thing I did was to make some ventilation holes with a sinister giggle that only Dave McQueen would appreciate. :eek:
 

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I was considering moving the R/R under the seat pan directly below the area of the ECU. The spacing of the bolt holes for the R/R is the same as the ECU. I was going to get longer bolts to hold both. Does anyone know if the heat from the R/R could be conducted through the bolts to the ECU thus causing a problem to the ECU?
 

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I was considering moving the R/R under the seat pan directly below the area of the ECU. The spacing of the bolt holes for the R/R is the same as the ECU. I was going to get longer bolts to hold both. Does anyone know if the heat from the R/R could be conducted through the bolts to the ECU thus causing a problem to the ECU?

GTRossi and i just built a new battery from the Dewalt 36v battery (A123 cells) and located it in the seat pan where the regulator normally sits. we drilled through the bolt holes in the seat pan to the other side, re threaded the holes, bought longer bolts, and mounted the regulator underneath and in the wind. originally it had small dress washers to give it some air so it wouldnt contact the plastic seat pan. i rode it pretty hard and then pulled the regulator off to see how much heat was hitting that plastic seat pan, turns out it was barely warm. just to be safe though i had some plastic standoffs that i painted black and put in place of the dress washers, and remounted the regulator.

it is possible that the wiring could go bad and melt down, but it is highly unlikely now that it would melt out the seat pan and screw up the regulator etc.

the new battery fits in the place perfectly as though it was designed precisely for the space, and with the location of the regulator and the shocks, its pretty well hidden.
 

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Will I get a new one?

I have an '06 S1K that just smoked the $hit out of its R/R. I read the beginning of this thread and saw mention of the old/new ones and how there is a problem with the new ones. I am having a real hard time finding the part number on it, but I'm pretty sure I have a 'new' one. Can I expect to get a replacement for this (now out of warranty), or am I going to foot the bill for it?

If I do have to purchase this, how much is this going to cost me?

...and drilled the fins for some circulation.
I hate to be that guy, but those holes drilled for circulation may make it worse. By drilling the holes, you have decreased the total surface area used for cooling. The better thing to do without changing the location of the R/R would be do turn it sideways and get cross ventilation on it.
 

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The better thing to do without changing the location of the R/R would be do turn it sideways and get cross ventilation on it.
I did that . . . and . . . mounted under the seat, took the guts out of the old one, milled off 1/3 off the back side, and bolted the new and old one together to increase the heat sink.

Can you yell I was pissed off that the first one failed.
 
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