Fried Reg/Rectifier

[Kato]

This is for bikes with the discreet 3-phase Stator/Generator and Rectifier/Regulator arrangement (Three yellow wires)

Most of us at some point have experienced problems with OEM Regulator/Rectifier used on pretty much the whole Ducati range, so time to do something about replacing the standard equipment R/R with a more efficient component.
I’m assuming that your R/R has failed at this point but no reason you couldn’t do as a preventive measure / upgrade if you were bored could be done in under an hour

First a basic troubleshooting process to determine whether you have a charging system failure.

A good Multi-meter is a pre-requisite.


Record your battery voltage under the follow conditions
1) Ignition off, unloaded battery.
2) Ignition on, headlights on, not running
3) Bike started, running at idle

Condition 1, should be at least in the high 12.x range if fully charged.

Condition 2, your voltage should not drop much below 12.0 at worst. (It may continue to drop – hopefully slowly! – As your lights will be discharging it. However this should be a slow decline)

If it does drop immediately into the 11’s, your battery is insufficiently charged – if it was just charged from a battery charger however, then it indicates your battery no longer has sufficient capacity to retain charge/supply current to load and should be replaced.

Condition 3 is what we are most interested in with respect to charging capability.
Voltage should be at least in the 13’s at all engine rpm. You may detect it will fall off slightly as you raise engine rpm. This is not atypical performance. A simple mod that can enhance your charging voltage to the battery can be achieved by this modification outlined in this thread. That should give you performance in the 14V+ range.

What if you have less than 13V?
First thing to check is the fuse in the charging circuit.

Next, examine the wires and connectors between the R/R output and the R/R input – are these charred/melted due to excessive heating? This is fairly common result of poor connection between the terminals.

A ‘cold’ resistance check for shorted diode/SCR:
Unplug both input & output plugs from R/R;
With your meter set to read resistance (use a diode test if the your multi-meter has one), test from each pin of the three pin plug, to both the red & green wired pins NONE of these should read short circuit (zero resistance); depending which way you bias the test leads, you may get some reading (from the forward bias) but it must absolutely not be a short. If you see a short on any of these readings the R/R is defective.

Next, do a resistance check on the stator (check at the cable connector going back towards the stator itself).
Measure between the three respective combinations of the three pins:
1-2
2-3
3-1
This time each of these should measure almost short circuit (very low resistance in order or about 1 ohm)

This next check is probably the simplest/quickest way of determining a stator problem - in majority of cases a bad stator will be indicated by failing following test:
Check resistance from any one pin to the engine earth – this should not read any indication – maximum resistance or open-circuit.
If you read ‘short’ in that last test, then your stator is .
(if open, it is not quite guaranteed your stator is good however - but in majority of cases a failed stator will fail this isolation test)

[Kato]

Check the AC voltage output from the stator with engine running:
Leave stator disconnected from the R/R and start the engine.
With meter set to read AC Volts check
1-2
2-3
3-1
All three should be the same value – any significant difference of one reading will indicate a bad phase and the stator is probably defective.
At idle this should be ~ 20V* and rise to ~ 70V* at 5K rpm.
I hesitate to use absolute numbers here as this can be different between models and test equipment and especially the engine rpm!
What you are looking for is same value between phases and like increase on each phase as rpm increases.
If any of the above tests raises suspicion, remover the cover & inspect the stator. It is simple to do and can set your mind at ease by seeing what it looks like.
Hopefully NOT with 1/3 of it a black charred mess!

If you have to replace the stator and R/R, especially because of a shorted R/R and excess current drain, be especially careful to ensure that your wiring has not burned. Replace any cable &/or connector plug that is not in good condition.

Now on to the alternative R/R replacement

- as aforementioned this is a good preventive upgrade measure with a better component, not necessarily limited to replacement on failure. Either way, process is the same.

Best widely available R/R on the market was the Shindengen FH012AA used on the late (06+) Yamaha FJR, 07+ Yamaha R1 among others this has now been now superseded by the better FH020AA

What makes it better is that is a MOSFET controlled device rather than the crude SCR shunt type that is on our Ducati's.
MUCH better voltage regulation and runs cooler too due to more efficient device and control circuitry.

The SCR shunt type consumes more energy in the Regulator itself than the bike is using and dumps a ton of excess current into the heat sink (feel yours & just see how hot it runs after a ride - don't touch it - you'll burn yourself - seriously!)
The problem is exacerbated because their efficiency goes even lower when they get HOT so it's a vicious circle. Heat is the number 1 killer of these devices.
Incidentally it’s a misconception that shunt type work harder with increased load i.e. higher-wattage lights, heated grips etc. - actually, the higher the load on the output, the less work the shunt regulator does in dumping that excess energy and will actually run cooler!!

The FET has extremely low resistance in conducting state and this’ results in a lower dissipated power from the device while conducting load current, as opposed to the SCR which shunts the maximum current across a significant volt drop, resulting in a higher dissipated power - and resulting temperature, much more so than the FET device.

Parts Needed for a direct swap
Shindengen FH020AA or FH012A0
Triumph link lead part number T2500676

[Kato]

If you want to make yet more improvement and replace the existing wiring for something altogether more robust then you will need

1 x FH020AA
2 x Furukawa Connectors
1 x 4 way am-phenol Connector
1 x 3 way am-phenol Connector

Cut the plugs from the 3 yellow wire coming out from the stator and and the red / green wires then replace with the weatherproof amphenol type plugs
Theses ones


Make up a lead with the other half of the Amphenol connectors at one end and the Furukawa connectors on the other

Furukawa

Amphenol




Hopefully you'll end up with something looking like this one


Have Fun

[utopia]

What a cracking posting, Kato.
Thanks very much indeed for a straightforward, easy to follow yet very detailed "how to", with all the info and pics needed to do the complete job.
Definitely worth a big sticky in my opinion.
And a second "thanks very much" from me.
Maybe even a third.

I'm almost disappointed that I replaced mine with an Electrex unit a couple of years ago (which I believe to be SCR type rather than Mosfet, but there is some uncertainty).

As far as I can tell, you've fitted yours under the tank. Any particular reason for this ? I'm guessing its partly to keep the connectors in a dryer location, but that will obviously tend to keep the unit out of the cooling blast of air too, and surely these mosfet units still need a good cooling even though you say they run cooler than the std item....?

Final question...due to the improved reliability of the mosfet, is it your opinion that a secondhand unit would be a safe buy ? I would never fit a used oem unit, but maybe its ok with these for a cheapskate like myself.......?

And a fourth "thanks very much" from me.

Originally Posted by utopia

Final question...due to the improved reliability of the mosfet, is it your opinion that a secondhand unit would be a safe buy ? I would never fit a used oem unit, but maybe its ok with these for a cheapskate like myself.......?

I'm also a cheapskate and recently bought the same reg / rec used from eBay to go on my KTM - I believe it came of a Multistrada 1200.

I bought the Furukawa connectors from this geezer:
http://easternbeaver.com/Main/Elec__...onnectors.html

IMO it should be fine for many years even though it's second hand... I got it for £10, so not a huge problem even if it does die...

[ductromso]

Im looking for an alternative RR that i can use on my 94 M900 with 2 wire stator . I bought an electrex rr and this one was no good ,so i replaced it with a used OEM RR i got from a friend . If you guys have advice for a better and more stabile RR alternative for an old 2 wired Monster, i will be happy for some hints !

[Darren69]

Originally Posted by ductromso

Im looking for an alternative RR that i can use on my 94 M900 with 2 wire stator . I bought an electrex rr and this one was no good ,so i replaced it with a used OEM RR i got from a friend . If you guys have advice for a better and more stabile RR alternative for an old 2 wired Monster, i will be happy for some hints !

I think you should be able to use the 3 phase reg on a single phase system, but you will have one less yellow wire to connect. Has anybody actually tried this to either prove or dispel my theory?

[Kato]

Originally Posted by Darren69

I think you should be able to use the 3 phase reg on a single phase system, but you will have one less yellow wire to connect. Has anybody actually tried this to either prove or dispel my theory?

Yes .....and yes it works without any problems

[Saint aka ML]

Originally Posted by Kato

Yes .....and yes it works without any problems

Yep all good as Kato says

[Mr Gazza]

This couldn't have come at a better time Kato...Thanks for really good info here.

I was planning to head off any reg/rec problems at the pass this winter, by simply replacing all the connectors with soldered Gold connectors as used on my electric model aeroplanes.

We use them on the models because they make a very good connection that handles lots of Amps with little resistance and have the benefit of emitting minimal RF noise (radio frequency), which can interfere with the radio control, but not a problem that I have ever had on a bike...

Your conversion is way ahead of my ideas Kato, and I think that is definatly the way I will be going. Especialy as you have explained everything in such an understandable and logical way.........Thanks.


....P.S..Shouldn't a topic like this be sticky-fied?

[Darren69]

Hi Gazza, Did a bit of googleing and found this guy who supplies all the required parts in various kits, either full diy assembly or plug n play. From what I can gather though the triumph plug does not have the same catch on the plug to lock with the other socket and has to be cable tied, so maybe the best option is the full diy jobbie.

http://roadstercycle.com/

[Mr Gazza]

Nice one Darren..Thanks for doing your homework..

The kits do seem a bit on the dear side though, and I have found that you have to be careful importing stuff and buying in a different currency.

First little take is from Paypal, who have a "special" exchange rate.
Then you may have to pay VAT on the goods when they arrive in the UK.
Then Royal mail may charge to bring it to your door and handle it through Customs.
Might be wrong though...Never bought anything from the US...I'm sure thier economy can manage without my input..

There's a good Yamaha dealer in Norwich (Tinklers), so I might see what they want for the reg/rec.
I found some very good connectors for my injectors on ebay so I will look there for those.

....Stiil not a sticky topic...??

[Darren69]

When I read Kato's thread I was interested in how much one would cost and a quick search on ebay concluded that they were £60-80 quid s/h and about £130 new just for the reg/rec unit so I'll be leaving mine with the stock unit for now in any case until if/when it fails but given that heat is the main cause of failure I'd already fitted a re-locator kit from TPO and picked up a cheap s/h unit from an ss for 15 quid just in case so I will see how it goes.

[utopia]

While browsing ebay for other electrical items, I came across these mosfet reg/recs, which are listed as being suitable for various late model Yamaha R1s.......

http://www.ebay.co.uk/itm/MOSFET-REG...item3396254a7b

The model number is FH012AA, which doesn't correspond exactly with Kato's recommendations of FH020AA, or FH012AO, but is sufficiently close to both that I'm hopeful that it might be a suitable fitment.
AND.... its only £27.
Can anyone tell me whether it will be suitable for my M750 ?

[Dennis menace]

What a great 'How To' - keep 'em coming.