Ducati Monster Forum

Moto Board => Tech => Topic started by: MonsterMadMarty on July 12, 2014, 06:33:53 PM

Title: 12120291A & B What's the Difference?
Post by: MonsterMadMarty on July 12, 2014, 06:33:53 PM
What's the difference between piston rings 12120291A and 12120291B?

And which, if any will fit the early carburettor 900's (93' to 97') pistons?

Cheers  [thumbsup]
Title: Re: 12120291A & B What's the Difference?
Post by: ducpainter on July 13, 2014, 03:49:35 AM
According to the online lookup at Ducati Omaha those numbers have been replaced by 12110401A...

but they say it's a piston pin.
Title: Re: 12120291A & B What's the Difference?
Post by: MonsterMadMarty on July 13, 2014, 04:58:47 AM
(https://i148.photobucket.com/albums/s24/martyscott717/e60ffbcbef20117d219e032ba496b0eb_zps6abdee65.jpg)
(https://i148.photobucket.com/albums/s24/martyscott717/8061efd83f9f4bc10c6ec8f1e9b5b364_zps92dacb28.jpg)
Title: Re: 12120291A & B What's the Difference?
Post by: ducpainter on July 13, 2014, 05:35:27 AM
Dunno what to tell you

A guess at the difference in the part#'s...

Ducati has A and B cylinders and pistons based on tolerances.

I think, but don't know, that the suffix of the number is to match with those pistons and cylinders.
Title: Re: 12120291A & B What's the Difference?
Post by: MonsterMadMarty on July 13, 2014, 05:45:38 AM
I was guessing from the Ducati logo B may just be a predecessor to A !!!

Did the actually pistons change when the 900 went from carburettors to injectors?
Title: Re: 12120291A & B What's the Difference?
Post by: ducpainter on July 13, 2014, 05:47:59 AM
Quote from: MonsterMadMarty on July 13, 2014, 05:45:38 AM
I was guessing from the Ducati logo B may just be a predecessor to A !!!

Did the actually pistons change when the 900 went from carburettors to injectors?
Could be.

I don't know.
Title: Re: 12120291A & B What's the Difference?
Post by: brad black on July 13, 2014, 06:50:41 AM
a last # or letter change is a part progression/supercesion.  they should be identical functionally i'd think, but check all rings are the same size and form.  i'm pretty sure all 900 top rings are dykes rings.  maybe different style oil ring?  dunno.