ST2 rectifier problem?
 

I think I have a rectifier problem on an ST2 (1997). The battery hasnt been charging well recently despite daily use and yesterday I noticed drop of power at high revs and occasional missfire. Then my ride was suddenly ended when the engine died completely and the battery didnt have the power to do anything except light the dash.
A call to Rich at Luigi Moto seemed to confimed my suspicion it is likely to be rectifier failure, and after a call to Craig at Motorapido I realised being a 1997 ST2 I may be in for £200+ for a new one (the later, 1999, rectifier is only £70). Electrexworld dont have any pattern parts at the moment ("it is being redesigned") although I need to check because at the time I thought I was looking for the later part.
Any advice on whether this behaivour sounds like a rectifier would be appreciated. Plus any potential alternative to the £200+ cost for new one.
I am really hoping it isnt a generator failure, as this is nearly £700!!
The bike is in the Chippenham /Bath area
Cheers

You can use the RR51 Electrex if you need too, I did. It's only got two wires so you do lose the charge light option. I also re-sited mine in the air flow of the intake for better cooling. I'm local too in Bath!

Thats great thanks for the advice. I will phone them again in the morning. It was the RR50 I asked about before - as the bike was registered in 1999. I only found out today when the frame no. was checked that it left the factory in 1997, hence the older part.

Is it a 2 yellow wire one or 3 ? I have a 2 wire one on the bay at the moment.
I could pull it if you want it ?

Mark

If it's '97 it's a two wire, I'd steer clear of the Ducati one though and get the Electrex.

Surely the later Japanese type that Ducati fitted to the 916 etc would be alright, but staying clear of the early metal lump of a reg/rec isn't a bad idea, Saying that I do know of some that are still working OK

Hopefully yes, but even these are prone to problems.
The RR51 is the Electrex that fits the 916's etc if I remember correctly.

Hmmmm... not so sure Kev, I read somewhere on an ST site that for the 97 model year, and only for that years, Ducati had a 400w single phase alternator which is not compatible with anything else

I have a spare early ST regulator in my garage-will check what type.

John

Just replacing the regulator without addressing the root causes of it's failure (undersized stator wires, shorting of the insulation-damaged wires inside the common sheath, and overheating of the regulator due to inadequate cooling inside the fairing) is a waste of time and money. Replace the wiring, eliminate the in-line connector and relocate the RR first.

http://www.ducatisportingclub.com/sh...ad.php?t=78401

Thanks for all the advice, looks like the way forward is new stator wires, relocate the rectifier, and use an new RR51 losing the battery charging light (which never came on anyway).

Assume this will work? Anyone know why this won't?

Worked for me. I Didn't figure out the stator wire issue until I was on my fifth regulator. Three were replaced under warrantee by Ducati. They had no interest in why they failed, so they just kept putting in a new one. I got serious when I had to pay for the next one.

Possible bad news:
Make sure you get the replacement right. The frist ST's ('97) ran on a unique charging system (400W) from Ducati which only lasted a year before being re-designed (450W) - probably because it was pants.

Possible good news:
Talk to Duccati UK. They may pay for free fitting of a new one as they know how bad the system was. I doubt there are many originals still running out there.
I know this sounds far-fetched for such an old bike, but they paid for mine when the bike was 7 years old.
At the same time, check that there are not any re-calls still outstanding on your bike (use the chassis number). There were 3 or 4 for these models and 2 of them were important.

Regards,
Mike

Thanks Shazaam & Mike

Will check out the system with Moto Rapido and if its not a 400w proceed with the improvements/repairs as above, watch this space for an update of whether this works!

Did you get a chance to look at this? Have sent you a pm

Mark,

do you still have this rectifier? I have sent you a pm

PM'd a reply

thanks mark, have passed that on