990 SMR cracked engine case - advise needed!

Discussion in 'Dakar champion (950/990)' started by cem, May 31, 2019.

  1. cem

    cem Adventurer

    Joined:
    May 31, 2019
    Oddometer:
    11
    Location:
    Daly City, CA
    My chain snapped and caused two 2” cracks in the engine case around the swingarm left pivot. The cracks go completely through and luckily the bushing prevented a blowout. Gruesome pics below…

    https://imgur.com/a/Nnct21v

    I see a few options for proceeding…

    Engine swap
    Lots of 990 SD engines to choose from on eBay but unlikely to find year and model match. Unsure of the plug and play nature.

    New case
    New cases are nearly double the cost of a used engine. Swapping the internals is outside my comfort level and is time-consuming.

    TIG welding
    Trying to find someone to do this is tricky and also will likely require the engine to be pulled if not having the case split apart.

    JB Weld
    This is maybe a terrible idea, however, I’m asking how serious are the cracks really. I’m obviously not a ME but I’m curious how widely distributed the stresses are since the swingarm pivot bolt anchors in the frame on both sides, the collar is sound, and 75% of the width of the engine case pivot “channel” is intact. In this scenario, I would slap a new drivetrain on and then monitor the cracks.

    I have lurked in this community for the last 5 years and learned so much about my 690 and 990. Any advice is highly appreciated!

    Charles

    -------------------------------------------------------------------
    Disclaimer
    I'm foolish for putting 12k miles on the drivetrain with a light maintenance schedule. There is no insurance assistance since this is mechanical wear-and-tear and no collision occurred. I should have seen this coming when I swapped the swingarm two months back.

    - I used advise instead of advice in the title. I know I'm incompetent with regards to written English.
    Perhaps a mod could be kind and edit the title, pretty please?
    #1
  2. AdvRonski

    AdvRonski They call me......Ronski

    Joined:
    Feb 4, 2007
    Oddometer:
    1,520
    Location:
    Finally made it to Fruita!
    That's a tough one. That area won't leak oil, as it's outside the crankcase area, but the swingarm pivot is a key engine mounting point, and stress and vibration are likely to propagate the crack. I'd vote for a used engine, but an SD will have a close-ratio transmission that you may not care for. Any other model engine will have the same trans as your SMR. I found an SD engine on ebay, and swapped the trans from my 950 adventure engine into it. I love this engine! More power than the 950, but there is a bit of work involved.
    #2
  3. cem

    cem Adventurer

    Joined:
    May 31, 2019
    Oddometer:
    11
    Location:
    Daly City, CA
    I’m leaning towards the swap because of the relative simplicity but hadn’t considered transmission differences. Thanks for your reply!
    #3
  4. cem

    cem Adventurer

    Joined:
    May 31, 2019
    Oddometer:
    11
    Location:
    Daly City, CA
    I just found a nice condition case for $800 shipped on eBay. It's for a 07' 950 SMR but the part numbers are the same with my 11' 990 SMR. I'm considering making an offer tomorrow morning.
    #4
  5. hennessyktm

    hennessyktm Still here...

    Joined:
    Apr 9, 2009
    Oddometer:
    251
    Location:
    Munster, Indiana
    JB weld and monitor the cracks. In the time being, search for a used engine or case. If the JB doesn't hold up, buy an engine or case.

    JB it!!
    #5
    sieg likes this.
  6. cem

    cem Adventurer

    Joined:
    May 31, 2019
    Oddometer:
    11
    Location:
    Daly City, CA
    I'm so conflicted since I just found a sweet case. I was skimming the engine disassembly/reassemble pages from the repair manual and got a bit overwhelmed. Get the case and send it to the pros. But be out $3k at least.

    So the lazy and cheap person inside me asks what's the worse thing that can happen with the crack given the bushings on either side and the fact that there are multiple motor mounts… I contacted 3 welders today. One passed, one called back and said they don't do this thing anymore and it would only be 50/50, and one was interested in the challenge after seeing the photos. I would need to get the bike to him one town over and potentially drop the engine for him to get it done, maybe even open the case. At that point, why bother with something that's not guaranteed, expensive and will have to be disclosed.

    I used some JB Weld earlier today on my 690 to fix a gas tank leak where one of the threaded inserts was installed for the rear bodywork. Maybe I'll practice some on some spare parts and give it a shot. I can always grind it off :)

    Thanks for your reply!
    #6
  7. mountaincadre

    mountaincadre Long timer

    Joined:
    Jul 18, 2012
    Oddometer:
    2,024
    Location:
    Mid Calder,Scotland
    I have a set of cases that I got free gratis from an inmate here, I was going to keep them for future use but your need is greater than mine, if you need them give me a shout,( obviously they are free, just cover the postage)M.
    #7
    cem, Amphib, DirtyADV and 3 others like this.
  8. skuikka

    skuikka Been here awhile

    Joined:
    Jun 23, 2009
    Oddometer:
    269
    Location:
    Finland
    KTM block casting welds nicely, I lost my sidestand mount a couple of years ago an welded it before the motor cooled down. The picture shows the composition of the cast (Hitachi Vulcan LIBS). If you decide to get it welded, the welder will hopefully like to know so he can choose the right filler. Personally I'd weld it. Cut the crack open, weld it shut and machine to original shape. The last part might be the most troublesome but a milling machine should do the job. Use the uncracked hole to align the hole for the welded one. If you remove the clutch cover, you can use the sealing surface to get the holes aligned vertically. I'd say that starting with removed and well cleaned engine with no oil inside, I'd spend an hour welding and maybe two milling to get it done. Including little lathe work to make an alignment stick for the swing shaft hole. Pre-heat wouldnt harm in such stressed place.

    Attached Files:

    #8
  9. skuikka

    skuikka Been here awhile

    Joined:
    Jun 23, 2009
    Oddometer:
    269
    Location:
    Finland
    On a second thought, with that much force, I'd look around the front sprocket bearing area quite closely. Might be some damage there too if the crack was caused by pushing the motor forward from the driveshaft.
    #9
  10. DirtyADV

    DirtyADV Long timer

    Joined:
    Jan 13, 2007
    Oddometer:
    4,396
    Location:
    SWEDEN, Norsjö
    I say weld to start with.

    I'm no expert by any means and that it requires a good welder that knows what he is doing for sure.

    Would say that most stress in that area would be that the engine wants to be pulled back rather then push forward? Does that make sense?

    Just weld it with the brushing in place? If there is some penetration of the weld being bushing going in with a long rotating to open that up?

    Should things not align superwell after thin down axle a tiny bit in a lathe.

    At least that is what I would have tried if it happened to my beater 950.

    The 990 I would maybe consider cases or replacing engine. But would probably go with welding.

    Good luck.

    /Johan
    #10
  11. cem

    cem Adventurer

    Joined:
    May 31, 2019
    Oddometer:
    11
    Location:
    Daly City, CA
    First off, thank you for the helpful details should I choose to proceed with welding. I am starting to understand the nature of doing things right when I'm often looking for the shortcut. This continues to drive that point home. Thanks again.

    I have never done a front sprocket swap on this bike so I don't have a "feel" reference but it rotates freely and silently. There are no visible cracks, bulges, or indicators of stress.
    #11
  12. cem

    cem Adventurer

    Joined:
    May 31, 2019
    Oddometer:
    11
    Location:
    Daly City, CA
    Thanks Dirty! So far we have votes for all solutions but I think welding is the clear leader.
    #12
  13. Sneeze Juice

    Sneeze Juice Been here awhile

    Joined:
    Mar 14, 2017
    Oddometer:
    696
    Location:
    Charlotte,NC
    Welder and a dream.
    #13
  14. cem

    cem Adventurer

    Joined:
    May 31, 2019
    Oddometer:
    11
    Location:
    Daly City, CA
    I'm currently waiting to hear back with estimates for the case swap or straight engine swap from the fine folks at http://desmotosport.com. I had a triumph and they did some servicing for me while I was still getting the hang of wrenching. Should have something Monday to evaluate.

    I'm not holding my breath but I have requested a quote for case swap from the local KTM dealer. They have flaked on replying to estimates for repair work in the past so we'll see. Either way, you know it's going to be crazy expensive. Labor is ~$130/hr and the part (at their price) is around $2200.

    I posted some status on the welders but I would probably reach out directly to some custom shops (builders, tuners, etc) not just straight welders.
    #14
  15. cem

    cem Adventurer

    Joined:
    May 31, 2019
    Oddometer:
    11
    Location:
    Daly City, CA
    Ha. Maybe more like welder and a prayer, and then some more prayers, and some good old cash.
    #15
    DirtyADV likes this.
  16. peterman

    peterman cop magnet

    Joined:
    Jan 2, 2006
    Oddometer:
    19,738
    Location:
    Springfield,,,,like the Simpsons,,,orygun
    If you were closer I'd say bring it to me and I'll weld it for you, it's what I do. I'd clean out the cracks with a carbide burr and a die grinder, make a little trench to fill, removing any paint or powder coating in the area, then tap or clamp the part to try to close the crack a bit, then weld the heck out of it and leave a big honking weld scar there for street cred. Maybe spray paint over the weld.
    To my eye it looks like it could be done in place no problem. Would definitley cost you some beers tho,,,:1drink
    #16
  17. cem

    cem Adventurer

    Joined:
    May 31, 2019
    Oddometer:
    11
    Location:
    Daly City, CA
    I had a welder come to the house this afternoon and confirm he can do the job in place. I'm going to remove the headers to give him increased working space and then tow it to his shop one "town" over. He suggested the exact steps you mentioned and quoted 3-4 hours for everything. I paid an hour for him to come to me and get a consult and we talked for 40 minutes. He used to have a 625 LC4 and he was asking a bunch of questions about my 690. Seems pretty chill.

    I'll report back when it's done. In the meantime, I contacted supersprox to see about getting some of their stealth sprockets (in 520). I have a new vortex aluminum 42t sitting around but I'm thinking about going steel.
    #17
    mountaincadre and nk14zp like this.
  18. peterman

    peterman cop magnet

    Joined:
    Jan 2, 2006
    Oddometer:
    19,738
    Location:
    Springfield,,,,like the Simpsons,,,orygun
    He's easily double the time it will take on his quote, you can tell him I said so. I could do it in an hour or less. 2 hours if you help me drink the beers you'll be bringing and we stop for safety meetings.
    Maybe that's why my shop doesn't make any money,, I'm not charging enough!:lol3 Hope it works out for you, not having my 950 is making me feel like I'm handcuffed to a fence. Mine is gonna need major engine work.
    #18
  19. cem

    cem Adventurer

    Joined:
    May 31, 2019
    Oddometer:
    11
    Location:
    Daly City, CA
    Riding my 690 feels like being strapped to a fart machine with a battery running out of juice.

    Sorry for your luck on the engine. Is there a thread on the situation?
    #19
  20. charlie264

    charlie264 Long timer

    Joined:
    Oct 27, 2007
    Oddometer:
    11,836
    Location:
    Blighty
    Engine. Old for spares. Welding isn't easy, you need a lot of material removed and filled then re machined. JB weld.....:imaposer
    #20