Clunck-oilspill-engine-no-more

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
User avatar
ir_joep
Posts: 107
Joined: Sun Jul 26, 2009 7:35 pm
model: 750 Sport
year: 1989
Location: Haarlem, The Netherlands

Re: Clunck-oilspill-engine-no-more

Post by ir_joep »

Overtighting me never :D :D :D :banghead:

I think I'm to blame and not the Italian motorcycle industry....

Twisted shaft or warped key I still have to find out.

Cheers Joep
User avatar
higgy
paso grand pooh-bah
Posts: 3327
Joined: Tue Jul 29, 2008 9:50 pm
model: 907 I.E.
year: 1992
Location: Hilltown,Pennsylvania
Contact:

Re: Clunck-oilspill-engine-no-more

Post by higgy »

I think I'm to blame and not the Italian motorcycle industry....
I think there are a few here that could take up that argument :beer: :beer: :beer: :lol: :lol: :lol:
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
User avatar
ir_joep
Posts: 107
Joined: Sun Jul 26, 2009 7:35 pm
model: 750 Sport
year: 1989
Location: Haarlem, The Netherlands

Re: Clunck-oilspill-engine-no-more

Post by ir_joep »

News from the rotor saga

Do not know what exactly happend:

senario 1: Rotor nut was too tight and did crack the rotor at some point and than it got stuck in the stator.
senario 2: The rotor nut was to loose so the rotor could rotate over the woodruff key which expanded the rotor and did crack it to the same effect.

Anyway, reputated tuner, like kaemna (www.kaemna.com) do not install a woodruff key so if the nut comes loose the rotor just rotates and will not create such a mess.

what is your opinion about not installing a woodruff key?

Cheers Joep
giocast
Posts: 136
Joined: Sat Sep 18, 2010 8:00 pm
model: 900 SS
year: 1990
Location: UK

Re: Clunck-oilspill-engine-no-more

Post by giocast »

If you meticulously study the cracks you will get a clue as to how it failed. depending what revs you were doing when it failed - in gear/out of gear will determine a lot. It's possible it was flung out centrifugally due to crack(s)?. I wouldn't run without a woodruff key personally - let's hear what others will say.
angelix
Posts: 338
Joined: Thu Nov 29, 2007 2:38 am
model: 907 I.E.
year: 1990
Location: UK

Re: Clunck-oilspill-engine-no-more

Post by angelix »

The woodruff key is there only there to "allign" the rotor to the shaft; what holds the two together is ONLY the nut, the shape of the shaft and rotor (usially they are conical) and the Nm applied.

on certain engines the woodruff keys are made of aluminium or plastic so that if the engine comes to a SUDDEN stop at high revs the crack shaft does not snap where the flywheel is fitted in case the Nut retaining it is not tight properly.
User avatar
higgy
paso grand pooh-bah
Posts: 3327
Joined: Tue Jul 29, 2008 9:50 pm
model: 907 I.E.
year: 1992
Location: Hilltown,Pennsylvania
Contact:

Re: Clunck-oilspill-engine-no-more

Post by higgy »

I would agree that the key is of not much help
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
User avatar
ducinthebay
paso grand pooh-bah
Posts: 1323
Joined: Sat Sep 03, 2005 12:00 am
model: 750 Sport
year: 1990
Location: SF Bay Area

Re: Clunck-oilspill-engine-no-more

Post by ducinthebay »

The Ducati manual for my 450 referred the Woodruff key as a Junk Key, inferring that is is not to be taken so seriously. I just sheared one on my 450 and it cause no problems at all. Woodruff keys should be softer than the crank so they don't deform the crank when they go.

Cheers, Phil
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
User avatar
ir_joep
Posts: 107
Joined: Sun Jul 26, 2009 7:35 pm
model: 750 Sport
year: 1989
Location: Haarlem, The Netherlands

Re: Clunck-oilspill-engine-no-more

Post by ir_joep »

Hi,

Phil: Good for you (and the 450) :cool:

Think next time I will do without the key. It will give me a peace of mind while I'm driving at 120 km/h or more.

On the other hand, there are thousands of Ducs driving with the key...

Thanks for all for your thoughts.

KR

Joep
User avatar
higgy
paso grand pooh-bah
Posts: 3327
Joined: Tue Jul 29, 2008 9:50 pm
model: 907 I.E.
year: 1992
Location: Hilltown,Pennsylvania
Contact:

Re: Clunck-oilspill-engine-no-more

Post by higgy »

A good medium grade of loctite will serve your mag and crank better than a key
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
Post Reply