help with alternator problems...

anyone have any experience with electrex brand alternators?

i've had months of electric woes with my 916 ever since a lowside at the track, which should have been nuthing more than cosmetic damage.

i've gotten rather sick of having to put the bike on a tender weekly, seems it doesn't wanna output more than about 13.2v, and drops to around 13v occassionally. And once i start doing long rides to uni in a few months i reckon it'll go after 3 days.

my mechanic offered me a new one he's got at a good price, but this might work out a little cheaper, and being a student i need ever spare penny i can get.

so far i've had to replace the battery, battery box, and regulator, and i'm still at square one after months and thousands of dollars and being stranded five times, so it seems the alternator is the only thing left to replace.

would this aftermarket one be any better than the factory unit?

any advice or ideas on what to do next would be greatly appreciated.

Sadly selling it might be my only option...

I am not sure what you mean by alternator. As far as I know from messing with mine. Your electrical system being a 916 is most likely a two phase which consists of a still(not rotating) copper Stator which surrounds a rotating rotor thats connected to your crankshaft. Its a very simple system and I have not heard of too many problems with those components themselves. Usually its the regulator that goes bad and starts eating batteries. If you are not afraid of working on your bike here are a couple of things I would suggest.
1. Drain the coolant and oil out of your bike
2. Remove the left engine case. All you need is an allen wrench to do this.
3. Inspect the wire connections going from the copper stator which go to a connection which runs across the engine to the rectifier. Its possible that you might have banged something loose during your crash and there's an intermittent connection in your charging harness which shows itself under the vibration of an operating engine. If you have replaced everthing else your problem probably lies in the wiring from your stator to your rectifer. I would go through all of it with a multimeter or have a mechanic who can do this for you if you don't know how.
Hopefully you will find the problem in there somewhere. I find the electrical systems to be pretty dependable with the regulator being the weak point in the system. I would also make sure all your connections especially battery are clean and corrosion free. Also do a general inspection of your wire harness looking for chaffed wires or corroded connections. Also check all your fuses. I have had my rectifier just go out on my six year old 748 so if you get six years out of a rectifier your doing alright. If you have a hanes manual or shop manual replacing the case requires you tighten the bolts in a specific order with a specific torque. don't forget to clean and reseal also. Hope this helps and don't give up. Electrical gripes are a frustrating pain in the ass but a competant mechanic should be able to figure this out for ya. If its the altenator then thats the first Ive heard of it. I wish I had my manual with me I could see which component is the alternator. I am sure some of the other guys around here can give you better advice. Good luck one way or another.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ian748L &raquo;</TD></TR><TR><TD CLASS="quote">If its the altenator then thats the first Ive heard of it. I wish I had my manual with me I could see which component is the alternator. I am sure some of the other guys around here can give you better advice. </TD></TR></TABLE>

Allow me to be the first then to confirm a generator (alternator) problem on an SBK My symptoms were battery rapidly dying (lights dimming, dash lights dropping quickly), engine choking and stalling from speed, etc. Went for a ride with no previous issues, stop for gas, fire up, ride half mile, die. Jump it, ride 1/4mi, die.

Via test of the wiring system and R/R, w.multimeter and finally removing the left side engine cover to get to the genny we determined it was shorting - as you suggested in the above case, Ian, the wire soldered to the copper mass was broken off a bit. Multimeter to the genny confirmed a short somewhere with it. Got a used replacement from BCM who came through when NOBODY else could and I was on my merry way.

Dukeboy, I second that you should check the generator. Let us know how it turns out.

Purchase the Haynes manual, it has all the info you need to diagnos and then replace the stator.

DW

The most common reason for a low alternator voltage output measurement is that the stator lead wire insulation is heat damaged. To diagnose this, strip away the common sheath that the stator wires run in and then separate the wires from themselves and from any grounded component. Then re-measure their output AC voltage. Examine the insulation for any softening due to heat damage that will cause them to short together at voltage levels lower than the alternator's rated output level. It's rare to see failed stator windings, but it's very common to see stator lead wires overheat and damage their insulation - because Ducati has supplied seriously under-sized wires - given that they have to carry 30-plus amps. Replacing the wires with a heavier gauge between the stator and the regulator cures the low voltage problem.

Here's the full explanation:

Ducati Charging System Failures

There's been a number of questions posted recently about charging system problems. This write-up is geared towards superbikes but has general application to all late-model Ducatis. It's probably more than you wanted to know, but save it, it may come in handy ...

Ducati charging system components, are prone to failure, especially on superbikes. When regulators first started to fail on the '95 916 bikes, Ducati changed the regulator design but that didn't stop the warranty claims. The first "improved" regulator that was sent out to dealers in 1995 was marked with a green dot of paint (to distinguish them from the older version) but otherwise appeared the same. They initially thought that it was just a bad batch of regulators but the failure reports continued. Not every bike experienced this problem, but some bikes experienced multiple failures.

The second iteration actually changed the regulator design and added an aluminum backing plate that performs three functions: it shields the regulator from the direct heat of the horizontal cylinder's exhaust pipe, it acts as a heat sink to help convect away the regulator's internal heat, and it helps to better direct cooling air from the fairing duct onto the regulator.



New Voltage Regulator Design

Regulators 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.

Note that if you fit one of these to an older bike you loose the functionality of the charging light.

The charging light is the first sign that the RR is about to fail. It will often start to flicker at above-idle rpm, sometimes requiring progressively higher rpm to extinguish it. Or, it may just come on and stay on without warning.

If this happens while you’re on the road, stop and pull the electrical lead wire (under the rubber boot) to your headlight to reduce power demands. If your battery was at full capacity before the regulator failure you probably have enough reserve capacity to run your bike for 50 miles or so if you have to limp home.

The second regulator redesign also incorporated a revised electrical connector so Ducati sold an upgrade wiring adapter kit to connect it to the bullet-type connectors of the original design. The apparent reason for this new connector style was that the original connectors would loosen and corrode so as to develop a high electrical resistance and overheat. Unfortunately the new connector style had the same problem.




Voltage Regulator Connector Overheating: Old Design/New Design

The regulator fails because there is often not enough cool air available to remove the heat generated internally by the unit and the internal electronics are damaged. At speed, outside cooling air is supplied directly to the regulator via a NACA-style duct opening in the fairing. It apparently wasn't big enough, so when the 998/748 was released, a larger duct was incorporated into the design.




Old Fairing vs. New Fairing NACA Ducts

In traffic however, there's not only no forced-air cooling, there's really no cooling air at all - the front cylinder exhaust pipe superheats the air in the lower fairing.

So the regulator still gets cooked at stoplights from its own internal heat and the nearby front cylinder exhaust header because there is such poor cooling air circulation in the lower fairing. The newer bikes have a revised fairing design with openings on the upper surface that may help convection cooling somewhat.





Overheated Regulator Encapsulating Material

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 below) and mounted it on the underside of the license plate holder facing the rear tire where it’s hardly noticeable.




Relocated Regulator for Better Cooling

Adding a regulator cooling fan was tried first, but the ambient temperature inside the fairing is just too hot to use as cooling air. Even though I wrapped the front header pipe in high-temperature insulation to reduce exhaust pipe heat transfer in the fairing to a minimum, the regulator surface temperature still climbed well beyond 160°F at traffic lights.

http://www.thermotec.com/produ....html

So far so good. The regulator still gets really hot while stopped, so it's no wonder that they fail when inside the fairing. If it's any consolation, Honda's do the same thing.

Then there's the problem of heat-damaged stator wires.

The initial charging system design had a 350 watt single phase alternator. Here's the design basis that Ducati used for sizing the system:

Design Basis





Note that the system wasn't designed to run both headlights simultaneously.

Note also that the power rating of the fuel pump assumes a clean fuel filter. Ducati fuel injection systems use a high pressure fuel pump powered by a DC motor that draws a fairly-high current and a dirty/clogged fuel filter will causes the motor to work harder and draw a much higher current. So the in-line fuel filter inside the gas tank requires regular replacement. A pump feeding fuel through a clean filter will draw about 2 amps, but this figure can rise to 10 amps with a dirty filter. Clogged fuel filters are a prime contributor to regulator failures.

Of course the electrical system doesn't normally operate with everything turned-on at the same time. So here's a more common operating condition:





It's important to note here that, given the obvious need to charge the battery, the stator wires will have to pass 29 amps (350 watts/12 volts) continuously. So I advise you to keep your bike on a trickle-charger whenever possible to reduce the demands on your charging system. Also, avoid the temptation to replace your battery with a low-weight, lower capacity unit. The principal advantage of using a larger battery is to be able to restart repeatedly. If you regularly don't ride long enough to recharge fully between restarts, stay with a larger capacity battery. A lower amp-hour battery will need to be trickle-charged more often.

A old battery on its way out will draw more current as the regulator tries to maintain its charge and is often the initial cause of an overheated regulator.

For 1999, Ducati redesigned the electrical system, going from the 350 watt design to a 500 watt three-phase system. (Three-phase alternators have three wires coming out of them, single-phase have two.) They produce an AC output that has a higher frequency than the earlier single-phase design so the regulator presumably has to do less work (i.e. less heat) conditioning the waveform and converting it to DC. The new alternator also has additional wattage available to run the lights, fuel pump, ECU and accessories but the higher output still has to pass through the regulator.

Which leads us to the second problem with the Ducati charging system ...

The wires running from the stator to the regulator are seriously undersized and their insulation becomes damaged from overheating.

The general 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 wire should have been used. 1999 (and later) three-wire 500 watt alternators produce a little over 40 amps so #8 gauge wire was needed (but not used.)

So you need to replace the wiring all the way back to the stator with a larger gauge.

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 or undersized wire 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 or electrical insulation 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 adjacent insulation. That’s why it’s best to solder the wires directly together and eliminate connectors entirely.

Generally though, 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.

Damaged insulation will complicate troubleshooting the system. The wires run in a sheath that causes them to touch along their length and particularly at the point where they enter the engine. If the insulation is heat damaged, it breaks down at higher charging rpms so the voltage between the stator wires will measure below spec.

The undersized stator wires generate the highest heat load at the points of highest resistance on both ends; connector to the regulator/rectifier (see above) and at the other end where they attach to the stator. Note in the picture below, the discolored heat-damaged insulation on the two yellow wires where they connect to the stator coil lugs.




Heat Damaged Insulation at Stator

Finally, I recommend installing an inexpensive digital voltmeter to get more information about the health of your electrical system. An on-board voltmeter will flag a charging system that is behaving erratically and intermittently prior to failure. When the charging light comes on it's too late.




Digital Voltmeter Installation

The model (Lascar EMV 1200) I use is shown here installed on a superbike: The meter's current draw is so small (3 ma) it can be left on continuously without draining your battery.

http://www.alliedelec.com/cart...V1200

To install, cut both lead wires to within an inch or so of the threaded stud. Solder a more substantial wire to each lead and run them directly to the battery terminals. Fit a piece of shrink tubing over the voltmeter's threaded stud and wires to prevent excessive bending or fatigue failure where they exit the meter.

As you can see, I mounted the meter directly below the water temperature gauge on my 916. You can run the shrink tubing covered wires down between the bracket and the instrument housing. The meter is so light-weight that no additional mounting bracket was required, the stiffness of the shrink tubing is enough to keep it from moving around. A small piece of foam placed between the bracket and the bottom of the meter will keep it facing you. If you mount it too rigidly it will see a lot of vibration that could shorten the life of the meter.

As a final note, use the above electrical load tables to see the effect that additional electrical loads will make when you make changes such as running both headlights together, added auxiliary equipment, or the use heated clothing.

The 1995–1998 superbike models were designed with a 350 watt alternator. The 1998 ST2 is unique, it was Ducati's one and only 450 watt single-phase system. For the 1999 model year 1999, Ducati redesigned the system going to a 520 watt 3-phase alternator. Make sure that your power demands during all expected operating modes don't exceed these levels. Adding additional electrical equipment or using a lightweight low-capacity battery, on pre-1999 bikes in particular, isn't very prudent.


Modified by Shazaam! at 7:07 AM 1/7/2005


Modified by Shazaam! at 7:11 AM 1/7/2005

If that's all the info you can come up with on a Ducati charging system Shazaam, then what good are ya?

wow,

thanks ian and shazaam for all the info.

i should have mentioned that i have already had the mechanic pull off the left casing and inspect the wiring, he did find a broken wire which he then repaired and it started to charge good again, but then after about a week or two it got erratic again, i did find slightly burnt connectors at the regulator end, fixed em up and started working a bit better, have followed the haynes diagnosis and every seems okay for the moment, and yet it just isn't outputting much charge.

have too bought a digital multimeter to keep an eye on things which is why i know its not putting out that much charge when riding, it isn't dropping at high rpm though, its just no going any higher than 13.2-3v at any point.

i may get the mechanic to upgrade the wires all the way from inside the casing may it has burnt through again somewhere along its length. just don't wanna spend 100s on a new generator if i don't have to, but at the same time i am wasting so much money trying other avenues which are all dead ends.

on a side note: when i had the casing opened i asked to get the flywheel lightened and he suggested you just remove it entirely on a 916, so he did, and maaannnn is it good fun now, i recommend it to everyone...

Anyone know what type wire is needed to relocate the R/R? I'm doing mine tomorrow and figured about 14G wire from Radio Shack would do it but I dunno...anyone?

Thx.

When you relocate the RR, the stator wires now quickly exit the fairing and run along the frame (good conduction and convection cooling) to the regulator. This is a much better heat environment that allows you to run an only slightly-larger AWG 12 gauge (SWG 14 gauge for you UK blokes) PVC coated replacement wire from Radio Shack.

You don’t even need to remove the engine cover.

The wires inside the engine don’t come in contact with each other until they exit the cover so even if the insulation overheats it can’t damage the regulator, and because of the hot environment, a larger gauge wire inside the cover isn’t going to reduce insulation operational temperatures much in this section of wire.

The approach that I took was to replace the wiring up to where it exits the side cover. I pushed a piece of shrink wrap tubing over each of the wires and into where they pass through the seal in the cover and left the internal portion of wiring alone since they are separated inside the engine.

DukeBoy, again the reason for your low and erratic charging output is that the portion of the stator output wires (that are forced to contact each other by the common sheath) are shorting out at higher engine rpm (i.e higher AC voltage levels)

A multimeter continuity test won't spot this. Trust me, replace the wires.

To the rest of you, do it as a winter project ... before you have problems.

i will do that thanks shazaam, is going to 8 gauge wire though overkill or stick with 10 gauge should be fine?

The main issue with replacing the stator wires is to reduce the electrical heating from the 30+ amp current they have to carry. A different aspect of this is that any in-line connector becomes a hot spot because, as corrosion occurs, that causes the connector resistance to increase and the heat generated to increase in this region. This damages the connector (melts the plastic ones) and overheats a few inches of wire both sides of the connector.

But that’s not the whole issue. Any wire, no matter what size, has resistance (so many ohms per foot) so any wire will heat up. Obviously the larger the wire, the less resistance it will have to current flow, and the less heating that will occur for a given current.

The type of insulation on the wire is also important to this discussion. Different materials have different temperature allowables for continuous operation. For example for 10 gauge (AWG) wire in 30ºC (86ºF) free air:

55A will heat high density polypropylene to 90ºC allowable
58A will heat Polyvinyl Chloride (PVC) insulation to 105ºC allowable
75A will heat Kapton, Teflon, and Silicone insulation to 200ºC allowable

So for example, silicone insulated wire should be used for higher current ratings or hotter operating environments.

The environment that the wire sees is important, and this is where Ducati engineers screwed-up. The above temperature ratings assume that the wires are located in 30ºC free air. The stator wires run first internally to the engine, and then are enclosed on a sheath that passes over the engine and internal to the fairing. So the insulation on these wires don’t see adequate cooling, they exceed their performance rating, and loose their insulation properties.

The portion of the stator wiring that run in the sheath is where insulation failure is critical. The stator wire are held closely together and insulation breakdown from heat causes them to short together at the higher output voltages at higher engine rpm.

The Haynes Manual, Section 9.21 has this warning:

Caution: Never disconnect/connect (i.e. short together) the alternator wiring with the engine running as this will damage the regulator/rectifier.

Most regulators fail because they get too hot inside the fairing, but this intermittent shorting together of the stator wires is the other cause of regulator failures.

So to answer your question ...

If you're relocating your regulator to behind the licence plate (which I strongly recommend) then the wires are routed outside (the hot environment inside the fairing) so use AWG 12 gauge PVC insulated wire.

If you're keeping the stock regulator location, use AWG 10 gauge. Use Kapton, Teflon, or Silicone insulated wire if you can find it, but PVC-coated wire from radio Shack will work, at least for a good while.

well, as an update,

got the alternator wires replaced with some teflon insulted cable (took over a dozen calls to find a stockist), and sadly it has done very little, still won't go above about 13.1v when hot.

so while i was considering getting the alternator rewound, a mate suggested pulling the electrics cable outta the left handlbar and see what she outputs. sure enough after that it jumped up to between 13.5-13.7, which makes me wonder if it is really that faulty?

so i'm considering wiring in a switch to allow me to turn my lights off, as i ride mostly during the day anyway, would rather solve the problem by conserving power than spending more money.

think its a viable solution?
kinda already spent close to a couple of thousand and gotten no where, this seems like a much cheaper option than getting it rewound...

Do a simple output voltage check of the stator itself, before going any furthur.

Take the multimeter set to AC VOLTS, connect it to the stator wires and disconnect the voltage regulator. Run the bike at 4 to 5K rpm. Check the AC VOLTS output. It should be anywhere from 50 to 75 AC VOLTS. If you get a reading in that range, the stator is doing it's job and the problem is elsewhere.

I've been through this several times with my own '95-916 over the last eight years, and it's always been the voltage R/R or the wiring. For a stator to actually go bad is very rare.........YMMV

I assume you mean you're considering getting the stator rewound? As TK suggests check it with a mulitmeter. As noted in my earlier post my stator or the bad wiring (attachment to the mass, which was the same thing to me) was bad. Multimeter to the mass yielded wacky #s so we knew that was the problem. A used replacement and my problems were solved.