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  1. #1

    Msx cranks and cases

    For some time I have noticed that a lot of of the 1200 MSX engines I receive to rebuild are damaged almost beyond reusing the cases. The factory machine work on the line boring leaves a lot to be desired. The cranks are loose in the cases and by the time you rebuild them there is a 10 to 20ths. groove in them. If you rebuild it this way the crank will be out of true before you tighten all the case bolts and the bearings will spin and take cases out rapidly. The fix for this is hard; re line bore cases, deck cases and add thick base gaskets. A good way to keep this from happening is, when you spend the money to rebuild your crank, spend a little more and use an O RINGED NACHI BEARING. This will hold the bearing much tighter in the cases and keep it from moving around at 6700 rpm. These are very high quality Japanese bearings (Better than OEM) and will save your cases. If you have a little wear they will prolong the life of a slightly damaged set. It is costly to line bore,deck the cases and re bore concentric hole for crank. If this topic has already been addressed then I am sorry for repeat but as these skis are getting some hrs. on them now, and more of them are needing rebuilds I am seeing more and more of this. The last 5 MSX motors I have rebuilt have had worn cases.1 set could not be saved. and after a bunch of work and making holders and tools to reach a triple my friend fixed them.Remember when you line bore the hole is bigger now so you have to cut the cases to make it smaller again now the whole is not round so now hole has to be cut round again,yada,yada,yada. I just finished 2 MSX motors this week and both and border line cases. shortblocksrus has a web page and builds cranks this way if you need it done Just some food for thought. THANKS: (P.S.) If you have more than 50 hrs. on your motor you should take apart and inspect if any wear has appeared you should consider this upgraded fix. In the photos below you can see where the bearings are just getting loose 59 hrs. also you can see the beautiful crank job using the Nachi bearings and welded ends. This is one of the 2 new cranks going into the 2 MSX's I have listed for sale.
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    Last edited by castaicsportsgarage; 11-06-2010 at 02:26 PM. Reason: add info

  2. #2
    Click avatar for tech links/info K447's Avatar
    Join Date
    Jul 2007
    near Toronto, Canada
    Have you observed this problem of loose fit crank bearings in both 2003 and 2004 MSX 140 engine crank cases?

  3. #3
    absolutely: I would guess most for the 2004 engines were built in 03 all by same. The 1050's being full circle cranks as opposed to pork chop in msx don't shake as bad especially at low rpm.

  4. #4
    Join Date
    Jul 2007
    Cedar Rapids,Iowa
    Thanks for the heads up.

  5. #5

    msx cranks and cases

    added pics

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