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Discussion Starter · #1 ·
I've only just gotten her, but she's started surging!

She was fine, and the only thing I did was drop the exhaust can to get to the rear brake. Now she surges! The only other difference I can tell is today we have about 100% humidity, and before this it was pretty dry.

A search of the forum shows surging to be a known problem for 2006+ models, but I haven't found any information of the 2005. Anyone out there experience this?
 

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FWIW Steve, that's an unusual report on this board... Virtually all MY2005 ST3 owners I've followed on this board have had nothing but good things to say. I might understand if you were getting some popping from a gap/bad fit between the pipe and the muffler, but surging? Maybe others have something to add.
 

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Check the fast idle switch. Make sure nothing is wrong with it or its cable.
 

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The throttle can be a bit sensitive and abrupt on and off especially at the lower throttle positions. I noticed it more on roads that had the occasional bump; my hand was moving the throttle. I eventually got used to it, I think. I either don't notice the occasional twitch on the bumps now or I have a lighter hand on the throttle and am not affecting it.

Bill_Anderson mentioned checking the fast idle cable; make sure it and the throttle cable are adjusted properly. Another possible fix is the Throttle Tamer discussed in this thread: http://www.ducati.ms/forums/showthread.php?t=62227. It is supposed to provide a smoother off/on transition.

Bill W.
 

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Discussion Starter · #5 ·
You know, that is one other difference... today was the first time I had to use the fast idle switch... I'll have to check to see whether it is hanging up...

As for the light throttle action, I expected that. And I've had bikes that were worse...
 

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My 2004 had a surging problem. I replaced the exhaust valve springs with the updated ones and that took care of it. But as far a I know, the 2005 bikes are supposed to already have the updated springs. They also have an updated ECU.
 

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My 2004 had a surging problem. I replaced the exhaust valve springs with the updated ones and that took care of it. But as far a I know, the 2005 bikes are supposed to already have the updated springs. They also have an updated ECU.
Yes, the closer helper springs were changed starting with the 2005 ST3. Didn't know about the ECU being changed. Was it a mapping change?
Bill W.
 

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I've only just gotten her, but she's started surging!

She was fine, and the only thing I did was drop the exhaust can to get to the rear brake. Now she surges! The only other difference I can tell is today we have about 100% humidity, and before this it was pretty dry.

A search of the forum shows surging to be a known problem for 2006+ models, but I haven't found any information of the 2005. Anyone out there experience this?
I purchased a used 2005 ST3 with 19,000 kms (11,000 miles) back in April and no surging issue so far. The only thing I have noticed though, is the quality of petrol I'm using makes a world of a difference, especially in the 7-9k range. I also add octane booster at every fill up since the 91 octane here in Canada is NOT really what they claim it to be. Given that the 05 has no O2 sensor, I removed the two horns located in front of the airbox and drilled six additional two inch holes. The seat of my pants tells my I have a little more power and the engine breathes a lot better.:D
 

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Yes, the closer helper springs were changed starting with the 2005 ST3. Didn't know about the ECU being changed. Was it a mapping change?
Bill W.
I believe it was a new mapping. The Service bulletin says: "In order to improve mid-range performance, in addition to the return spring you must replace the existing ECU part number 28641001F with the new ECU part number 28641001L".

It also says the S/N cutoff is 4B0003609. New bikes after this number got the updated ECU.

I never have been able to figure out the ECU numbering system and how to know which ECU I have. Mine has these two numbers on the stickers: sb321cpy and st3ducati1050. These do not match any part number in the parts book. If I follow the parts book, it looks like there were in fact 4 different part numbers for '04 and '05 bikes.

For 2004 bikes,
286.4.090.1C was replaced by 286.4.100.1C which was replaced by 286.4.100.1L (the one in the service bulletin)

For 2005 bikes,
286.4.100.1F was replaced by 286.4.100.1L (again the one in the service bulletin)

Colin
 

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Colin -
Thanks for ECU info from the service bulletin. Hadn't seen a copy of it.
Bill W.
 
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