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Title: Frame cracked! Post by: Dmitry on February 14, 2015, 01:23:50 PM Hello everyone!
On my Ducati Monster M900 (1997) cracked frame. You can see it on the photos. Crack was discovered after buying the motorcycle. What do you think, how long i can ride on this frame, if I ride on good roads? Photos: http://ipic.su/img/img7/fs/1.1423948994.jpg (http://ipic.su/img/img7/fs/1.1423948994.jpg) http://ipic.su/img/img7/fs/2.1423949008.jpg (http://ipic.su/img/img7/fs/2.1423949008.jpg) http://ipic.su/img/img7/fs/3.1423949022.jpg (http://ipic.su/img/img7/fs/3.1423949022.jpg) Title: Re: Frame cracked! Post by: Howie on February 14, 2015, 01:48:41 PM Weld ASAP! Also move post to Tech.
Title: Re: Frame cracked! Post by: Speeddog on February 14, 2015, 03:43:19 PM Weld ASAP! Also move post to Tech. Yes, get that welded up, do not ride it that way. Confirm that both motor mount bolts are not broken, and are tight. Also inspect the mounting areas on the crankcase for cracks. Title: Re: Frame cracked! Post by: ducatiz on February 14, 2015, 07:11:57 PM ouch, that's pretty bizarre
Title: Re: Frame cracked! Post by: monsta on February 14, 2015, 11:36:43 PM Been known to happen before... this was mine,
(http://i133.photobucket.com/albums/q41/monsta904/CIMG1668.jpg) I re-inforced it (plus the lower X section and braced the headstem) with some gussets for the fix... (http://i133.photobucket.com/albums/q41/monsta904/CIMG1674.jpg) (http://i133.photobucket.com/albums/q41/monsta904/CIMG1764.jpg) Title: Re: Frame cracked! Post by: Dmitry on February 15, 2015, 02:31:22 AM Yes, get that welded up, do not ride it that way. What do you think about this?Confirm that both motor mount bolts are not broken, and are tight. Also inspect the mounting areas on the crankcase for cracks. http://ipic.su/img/img7/fs/IMG_2258.1423996266.jpg (http://ipic.su/img/img7/fs/IMG_2258.1423996266.jpg) Title: Re: Frame cracked! Post by: Dmitry on February 15, 2015, 02:37:09 AM Been known to happen before... this was mine, Thanks for the photos! I will do about as: http://ipic.su/img/img7/fs/IMG_2258.1423996266.jpg (http://ipic.su/img/img7/fs/IMG_2258.1423996266.jpg)(http://i133.photobucket.com/albums/q41/monsta904/CIMG1668.jpg) I re-inforced it (plus the lower X section and braced the headstem) with some gussets for the fix... (http://i133.photobucket.com/albums/q41/monsta904/CIMG1674.jpg) (http://i133.photobucket.com/albums/q41/monsta904/CIMG1764.jpg) Title: Re: Frame cracked! Post by: Dmitry on February 15, 2015, 02:41:07 AM Been known to happen before... this was mine, How to think, how could this happen?(http://i133.photobucket.com/albums/q41/monsta904/CIMG1668.jpg) Title: Re: Frame cracked! Post by: monsta on February 15, 2015, 02:52:04 AM What do you think about this? http://ipic.su/img/img7/fs/IMG_2258.1423996266.jpg (http://ipic.su/img/img7/fs/IMG_2258.1423996266.jpg) how thick is the gusset you have there? Title: Re: Frame cracked! Post by: monsta on February 15, 2015, 02:55:08 AM How to think, how could this happen? fatigue... High stress area... poor welds....combination of all? Title: Re: Frame cracked! Post by: Dmitry on February 15, 2015, 03:15:13 AM how thick is the gusset you have there? 5 mm. it's okay?Title: Re: Frame cracked! Post by: monsta on February 15, 2015, 03:35:29 AM yep...
Title: Re: Frame cracked! Post by: Dmitry on February 15, 2015, 05:03:17 AM Been known to happen before... this was mine, How long you ride with crack? When found her...(http://i133.photobucket.com/albums/q41/monsta904/CIMG1668.jpg) Title: Re: Frame cracked! Post by: Howie on February 15, 2015, 06:00:40 AM I would not go any further than nursing it home if I didn't have to go far. Once it cracks through you will be on the ground. Also, do follow Speeddog's advice to check the motor mount bolts and case. Looseness there can cause that crack.
Title: Re: Frame cracked! Post by: Blackout on February 15, 2015, 08:59:58 AM Mine has been cracked at the same site on both sides for years. Probably pretty reckless on my part but I still ride the piss out of it. I'll have to pull the engine to gusset weld it.
Title: Re: Frame cracked! Post by: Speeddog on February 15, 2015, 10:22:44 AM The frame is dependent on the motor mounts being sound; both that the bolts are tight, and the engine cases aren't cracked.
As long as that condition is maintained, the frame is triangulated by the motor itself, and it's not going to crack there. Both of those tubes are then only loaded in tension and compression, and they can handle that with no problem. With motor mount bolts loose, or broken, or engine cases broken, the frame is no longer effectively triangulated. That section then has to carry load in bending. Those tubes aren't anywhere near big enough to do that, and the welds in that area compromise the bending strength. Title: Re: Frame cracked! Post by: Dmitry on February 15, 2015, 10:51:28 AM I would not go any further than nursing it home if I didn't have to go far. Once it cracks through you will be on the ground. Also, do follow Speeddog's advice to check the motor mount bolts and case. Looseness there can cause that crack. You're right! Motor bolts have been loosened! I tightened them. Is it true that frame could crack because of this?:(Title: Re: Frame cracked! Post by: Dmitry on February 15, 2015, 10:53:37 AM The frame is dependent on the motor mounts being sound; both that the bolts are tight, and the engine cases aren't cracked. Thanks for the reply, Speeddog!As long as that condition is maintained, the frame is triangulated by the motor itself, and it's not going to crack there. Both of those tubes are then only loaded in tension and compression, and they can handle that with no problem. With motor mount bolts loose, or broken, or engine cases broken, the frame is no longer effectively triangulated. That section then has to carry load in bending. Those tubes aren't anywhere near big enough to do that, and the welds in that area compromise the bending strength. Title: Re: Frame cracked! Post by: Dmitry on February 15, 2015, 12:09:15 PM Mine has been cracked at the same site on both sides for years. Probably pretty reckless on my part but I still ride the piss out of it. I'll have to pull the engine to gusset weld it. Show your crack :D I want to see photos.Title: Re: Frame cracked! Post by: Howie on February 15, 2015, 02:35:30 PM You're right! Motor bolts have been loosened! I tightened them. Is it true that frame could crack because of this?:( Since you read Speeddog's explanation... I would still fix it before riding though. Then again, I am very conservative on the advise I give to others. Closely look at the rear engine case where the motor mount bolt goes through to confirm there is no crack. Title: Re: Frame cracked! Post by: brad black on February 16, 2015, 03:23:19 AM bolt it up before welding it too.
bob brown ran a new rail above the v, pretty much continuing on the horizontal rail from the front when he was racing an 851, and he says it stopped the cases cracking. which they did a lot of. Title: Re: Frame cracked! Post by: BK_856er on February 16, 2015, 10:23:22 AM Reminds me I need to check my monster frame bolts again!
Monsta's excellent reinforcement looks a bit like what's on my 749s frame from the factory (i.e., original). BK (http://i60.tinypic.com/2v1kfa9.jpg) |