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Discussion Starter · #1 ·
what do I do now?

we went for a ride today & i was showing one of my fellow riders the new crankcase breather i installed when i noticed there was a film of oil on the rear hugger.

at first i thought it was the breather letting a bit of oil by, but after feeling the breather, it was dry. So i looked closer & $hit, this is what i found.

A cracked casing!!!

What's the go, how can this happen?? It doesen't appear to be loosing anything but a mist of oil. But it's along one of the structural through holes that the engine hangs from the frame by.

Can i weld it up?
What do i do??
has this happened to anyone else?

This is my first attempt at posting pictures. if they don't come out i have uploaded three files,
Case2
Case4
Case5
to the miscellaneous, Crashes & Wrecks, section.

i really hope there's a positive answer to this dilema!!

[http://www.ducatimonster.org/cgi-bin/ImageFolio3/imageFolio.cgi?img=&search=engine&cat=all&bool=and]

[http://www.ducatimonster.org/cgi-bin/ImageFolio3/imageFolio.cgi?img=&search=engine&cat=all&bool=and]

[http://www.ducatimonster.org/cgi-bin/ImageFolio3/imageFolio.cgi?img=&search=engine&cat=all&bool=and]

http://www.ducatimonster.org/cgi-bin/ImageFolio3/imageFolio.cgi?img=&search=case&cat=all&bool=and
 
G

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was the crashed?
from your other posts sounds like you are a good mechanic.
weld it, my 750 was wrecked when i bought it, and the engine case was cracked in the same spot.
took the engine to the welding shop, made sure the crack was closed up tight.
the welder made sure the weld area didn't get to hot.. so he took his time.
3400mi later everything is fine.. very small wet spot where the cases join above the swing arm pivot.. cases should be split and resealed.
 

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First thing I would do is take it to the dealer and see if they would contact Ducati and see if they will do anything. Yours is not an isolated case they have strengthened the cases a couple of time over years for just your problem. They may not do anything but it is worth a try. It can be welded and that would probably be the cheapest fix but rarely is a weld as strong as the original casting. Changing your engine isn't terribly expensive and it is a great opportunity to do some mods.
 

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Changing your engine isn't terribly expensive and it is a great opportunity to do some mods.
Huh? Is there a single more expensive part on a bike?

Interesting perspective Alex. :-/
 

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Not slagging anyone's responses so far, but, just so y'all know what he's facing here...

Chris resides on the island of Papua New Guinea, north of Australia. Somewhat primitive location (probably a gross understatement). No Ducati dealer, and IIRC, no motorcycle dealer, at least within any reasonable distance. May not even be a TIG welder on the island....

Here's the pics, folks:





 
G

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drat that doesnt look good.

wonder how good jb weld would work IF you could get it there?

from it pic it almost appears that it started at the bolt (pic 2). Overtightened and formed a stress fracture?

any US Naval vessels (or Aussie Navy) ever come to NG? If so i bet you could convince a machinist on board to help out if you ply them with liquor at a local bar.

Just a thought...

How far across does the crack go? to the cover on the otherside?
 

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Discussion Starter · #8 ·
Hi Guys, just got in to start work, thought i'd post this last night so i could get a few reply's, and there is, that's great, thanks.

the crack goes right accross from the (i'm guessing it's the neutral switch) to the centre line of the engine where the two halves meet.

OT, how long ago was your casing welded & does it look like it will stay welded, or is it opening up? The thought of splitting the engine casing to re-seal sorta scares me, as there must be some sort of measurable end float & shimming that would need to be re-checked?? I'm assuming!

Nick's right, there isn't so much as a bike shop here, let alone a Ducati Dealer.

I'm hoping welding will be a reasonable fix, until i can facilitate a more permenant remedy, which i guess is a new casing. Like Don said, good excuse for Hi-comp's ect.

I'm thinking for the repair, drilling a 1/16, 1/8 hole at the end of the crack, then grind a "V" along the crack with a Tungsten bit, then stich weld alternative ends, 1/2 an inch at a time, so as it doesent get to hot. Has anyone had experience with this. If i can get the proceedure right, i'm sure i can find a decent Tig Welder here, just not a Ducati tig welder.

What's underneath there, it it the Gear selector Mechanism?

Do you think there would be any come back on the Aussy Importer as Don Suggested?

Could the impact from Hitting the Dog have done this. (i'm thinking no, but may be wrong)
 
G

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the weld was done 1 yr ago. looks great so far 3400mi. but as i mentioned the seeping oil, where the case halves meet.
 
G

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where its cracked looks the same as mine.
i went to look at parts fish, and the casting looks like where the swing arm pivot shaft passes through is sort of tubular.
so if the outer part is cracked, so might the inner part.
like i said mine was welded. i did not disassemble the engine.. maybe i should??
 

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Discussion Starter · #13 ·
Got the engine out yesterday afternoon, & will take it to a guy that's meant to be a wizz at Tig Welding. Will let you know how it goes.

My concern still is, "What Caused this?"

Is this a common problem with Duc casings?
I dropped it some months ago, but only slid on it's side & i have a photo which i zoomed in on & there was no crack after it was back on the road.
What about the dog? Surely the stresses through the frame couldn't have done this? Otherwise you'd expect there would be something wrong with the Steering head as well, as it took the bulk of the impact?
Could you possibly ride a bike too hard, to cause this??

The frame didn't kick out of square when we pulled the through bolts out either??

It would be nice to know the cause, so it can be prevented from happening again after repair.

Anyone got an explaation.
 

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Man... what a disheartening discovery to make. My condolences, truly. I hope with some creative welding and finishing this can be effectively repaired.

I believe the suggestion that overtorquing the fastener is the most likely cause of this fracture...
"... from it pic it almost appears that it started at the bolt (pic 2). Overtightened and formed a stress fracture? "

Not knowing exactly how these motors are assembled I may just be just talking out of my ass here but... if this is a bolt that passes through the head into the cylinder, I suspect the culprit may possibly have been an incorrect fastener length... or a fastener with the incorrect washer thickness that allowed the bolt to run completely to the bottom of the bore. Torquing from this point would simply drive the bolt into undrilled/tapped material, would it not? The crack may have occurred at the time of the actual torquing, gone unnoticed and simply worsened over time from typical motor vibration.

Anyway... no matter how you slice it, it still sucks something horrible.

Best of luck.

Christian
 

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There is no way that bolt could be the cause of the crack. The only reason that bolt is there is to ground the battery. You should take this to a ducati dealer before having it welded and conplain if it is still under warr. You will need to make sure the area is super super clean before welding. This cast aluminum is the same type that transmission housings are made of. I remember trying to weld on way back with a TIG when I was a welder and the thing just melted and collapsed on me. On the second one I welded, I ended up using a aluminum arc stick to do the job and that worked because it welds faster. Make sure this welder guy is either really good or garrenttees his work. He could end up causing more damage.
 

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Discussion Starter · #16 ·
Christian,
I guess buying a bike second hand, you just never know. I will take good care to ensure all the correct Torque figures are used when re-assembling. The only real bolt in that vacinity is the through bolt that holds the engine in the frame.

it was quite tight & fairly rusty through the frame section, but it didn't need to be overly persuaded out, so again a mystery.

Although it seems strange that the rear through bolt (which is the one closest to the crack) terminates into a solid plug inside the frame tube. Where the front Through bolt has a nut on the end.

Maybe this has something to do with it. The front bolt with the nut obviously would allow a hinging action. But the rear bolt if overtightened is locking the motor rigidly to the frame, which defies all reason when everything else is pivoting or swinging.

Maybe these two forces fighting against each other could be the cause of the problem.

I jus can't understand why this would be. Maybe someone more ophay with building Duc's could add some light.

I'm quite seriously considering drilling out the internal thread & finding a nut to suit. Maybe even drilling into the end of each bolt & machining some grease nipples into each end????

They are starting the welding this afternoon, so fingers crossed it works!!
 

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Discussion Starter · #17 ·
Andrew,
Unfortunately mate, she's a 95 900M, so i don't think Ducati would honour any warranty, and the fact that there is no Ducati, no Bike shop in this country makes things just a bit harder.

This is a "Fix it or F__k it" kinda deal, if it works great, if not, well i would have had to airfreight the engine to Australia, get it rebuilt & air freight it back again annyway.

But as per one of my earlier posts, i would really, really, like to know the cause. Why the hell did it crack there??
 

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Chris,

The swingarm is mounted solely on the motor, so all loads (other than pure vertical) at the rear wheel are carried only through the motor.
Your bike's nine years old, may have had a hard life before you got it. May have been run hard with worn out swingarm bearings, that puts big impact loads into the cases. May have been run with the front motor mount loose, that will hammer the back mount bad. That crack was most likely due to repetitive big loads. You'd remember a single hit big enough to crack that.
You want both engine mount bolts to be tight, so the swingarm loads that pass through the motor are shared between both mounts.
Good luck with the welding, that's your best bet now.
 

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What about JB weld? I remember when I was a little tyke I took my dad's 250 Shadow and ran it over a curb (why? I thought it would be fun of course)...and cracked the underside of the engine. State Farm totalled the whole thing saying it wasn't worth getting fixed so we bought it back for a few hundred bucks...slapped some JB weld on there and it ran great with no leaks for another 4K miles. No heat so the aluminum would be safe and even though it may not be permanent it would still last quite a while.
 

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Chris,

The swingarm is mounted solely on the motor, so all loads (other than pure vertical) at the rear wheel are carried only through the motor.
Your bike's nine years old, may have had a hard life before you got it. May have been run hard with worn out swingarm bearings, that puts big impact loads into the cases. May have been run with the front motor mount loose, that will hammer the back mount bad. That crack was most likely due to repetitive big loads. You'd remember a single hit big enough to crack that.
 
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