[mkwilcox]

I'm looking for some guidance. I am currently re-assembling this bike, and I find that I am missing the (per Duc Service Manual) the "Generator Rotor". I've seen it also described as the Alternator magnet. This part is keyed into the crank shaft next to the flywheel.

After searching in vain, I have not been able to find this specific part. (I found one in Germany over the weekend, but they canceled my ebay order after discovering that they didn't actually have the part in stock...

The online Ducati Parts Catalog ST2 2000 Sport touring Ducati motorcycle # DUCATI Online Genuine Spare Parts Catalog doesn't show this part...

My questions are:

1. Does anyone know if this part is also used in other models/brands, and do you have a part #? Moto Guzzi looks promising, guessing seems risky.

2. Does anyone know of a 'robust' parts supplier who I could reach out to?

3. Does anyone have or know of a good source for a used part?

I've seen references to an alternator 'kit', but no details that this kit includes this part. Also the kit is priced at about $500. At this price, I might as well get a complete engine.

Thanks in advance for any assistance.

 

[TrialsRider]

Found lots of references to people upgrading older Ducati models with the 3-phase rotor magnet from an ST2 so I guess we know where all the used ST2 magnets are disappearing.

Also found all sorts of possible part numbers but nothing definite for 2000. Is your Y2K Ducati fuel injected or carburetor equipped? Fuel injection puts higher demands on the electrics so there 'might' be a difference in the charging system. Odds of the Sport Touring model having anything unique compared to other models is slim.

 

[Classic250]

Since it's basically magnets pressed into alloy, why are you looking to replace it? Is the keyway stripped?

 

[mkwilcox]

My ST2 is fuel injected, was crashed while stopped at a stop light, and then served as a parts bike. Some obvious parts were missing such as fuel pump, rear wheel, water and oil radiators.

Since I am sucker for neglected and crippled bikes, this one looked (still does) like a fun one, and I wanted to scratch my 2 valve Ducati itch.

Pulling the left side cover off to replace the starter (!!) it quickly became apparent that the magnetic rotor was missing (and the flywheel castle nut was bodged).

The only rotor that I could find was in Germany, but turns out that they were out of stock.

Since my initial post, I did some further digging found Jodi at: Motorcycle Parts: BMW, Moto Guzzi, Ducati. Many Brands in Stock. Bosch, Mahle, Valeo, EnDuraLast, NGK, NTK, BMW, Ducati Energia, Duke Cannon, Sachse, Westco, Deka, Motorrad Elektrik, BERU, BMW and More... who thinks that they have the part, and they have shipped it to me. (Jodi was awesome, and I've seen this supplier show up in various other forums, so I have a decent amount confidence that this will work out).

I am also missing a spacer and the key, but I'll cross that bridge once I get the right rotor.

If the rotor turns out not to fit, I may go down the engine swap with an air cooled carbed 2 valve motor. Either way, I am not in a great hurry as I have plenty of other projects to fill the gaps during the down times.

TrialsRider, yes I found #'s such as A4959, RO93, 264401438, 26420551A, 26540232A... Each source seems to have a different #, and inconsistent definitions between the various rotors, and rotor/kit combinations. I suspect that the rotor is different between a 3 phase and 1 phase motor (or I'd open up my ST4 1 phase motor for markings...)

Either way, thanks for the responses. I'll update once I learn more.

Thanks!

 

[Classic250]

Ah, ok. Your post showed the rotor and I was curious why you wanted to replace it. The key should easily be made by cutting down the appropriate sized metal lathe bit.

 

[mkwilcox]

Agreed. I should have mentioned that I lifted the photo from one of the forum writeups, and I do have a big old Logan lathe here ready to make what ever round things that I may need.

 

[brad black]

the photo you have is a single phase alt rotor. nothing like a 3 phase. all st4 are 3 phase - 1999 was the first year of 4v 3 phase alts.

this is a 3 phase alt rotor. not sure of aftermarket options, it's a pretty unique and never fails, so low demand part. lots of s/h ones on ebay or someone like mike at gotham should have a shitload of them.

the stator looks like this and bolts into the alt cover. lots of aftermarket options - electrexworld, ricks, etc. it's a part that fails.

 

[TrialsRider]

Curious almost looks like there is only 2 wires coming out of that 3 phase alternator, a 3 phase alternator by rights should have 3 wires for output.

 

[mkwilcox]

Update: The fog is starting to clear.

The net is that I don't think that I am missing this part, and that the workshop manual is in error.

1. I received the Jodi from Euromotoelectrics.com the 'round thing with magnets and a keyway'. The hole is too small for the threaded part of the crankshaft... Regardless, Jodi's service and response was exemplary.

2. Without this part, i.e. with just the flywheel, there are sufficient threads to properly torque the castle nut which supports Brad's point that this is not needed.

3. Ducati Parts USA replied with part # 27610281A for the flywheel, which also supports Brad's point.

4. Below is a screen shot from the Service Manual. #4 is what caught my attention. It seems that the manual is in error.

5. Indirectly related, I looked, and was surprised to see 3 AC wires from my 1997 ST4. From researching an ST4s engine swap into and ST4 I expected to see only 2 wires, 1 phase. Happy days, and my 110k mile ST4 continues to run fantastically.

While it will be some time before I'll be able to get the ST2 started to verify charging, I think that I'm good (although I'll probably replace the regulator as a matter of course.

Guys, huge thanks for your thoughtful responses! I will update if I learn anything further. The more that I learn, the more that I find that I don't know.

 

[brad black]

Curious almost looks like there is only 2 wires coming out of that 3 phase alternator, a 3 phase alternator by rights should have 3 wires for output.

i didn't look at the number of wires, so you are correct - that photo is of a single phase stator.

but you'll note that i said "looks like". i just found a stock photo on an ebay listing to illustrate to the op what he needs to be seeing, because he really has no idea here.

if you remove the alternator cover on a belt drive ducati engine and turn it over, you will see one of two possible alternator stators types. if it looks like the photo above, it's 3 phase. if it looks like the photo below, it's single phase.

single phase alt stator

 

[brad black]

Update: The fog is starting to clear.

The net is that I don't think that I am missing this part, and that the workshop manual is in error.

1. I received the Jodi from Euromotoelectrics.com the 'round thing with magnets and a keyway'. The hole is too small for the threaded part of the crankshaft... Regardless, Jodi's service and response was exemplary.

2. Without this part, i.e. with just the flywheel, there are sufficient threads to properly torque the castle nut which supports Brad's point that this is not needed.

3. Ducati Parts USA replied with part # 27610281A for the flywheel, which also supports Brad's point.

4. Below is a screen shot from the Service Manual. #4 is what caught my attention. It seems that the manual is in error.

View attachment 107079


5. Indirectly related, I looked, and was surprised to see 3 AC wires from my 1997 ST4. From researching an ST4s engine swap into and ST4 I expected to see only 2 wires, 1 phase. Happy days, and my 110k mile ST4 continues to run fantastically.

While it will be some time before I'll be able to get the ST2 started to verify charging, I think that I'm good (although I'll probably replace the regulator as a matter of course.

Guys, huge thanks for your thoughtful responses! I will update if I learn anything further. The more that I learn, the more that I find that I don't know.

it's not fog, it's the wrong manual. the manual you show is 97-98. it's not in error, it's showing exactly what a 97-98 looks like. the water cooled engines went to 3 phase alt in 1999. get the right manual.

you can't have a 1997 st4. st4 production began in sept 1998 for 1999 model year bikes. yes, it will have 3 wires as it has a 3 phase alt.

 

[mkwilcox]

My error, the ST4 is a 1999. I also didn't realize that I didn't get the 2000 Service Manual. Thanks again guys for all of your input!