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  1. #1

    SL 750 crank out of index?

    just got a 95 sl 750 that didn't run was told something wrong with engine. Checked for compression when i brought it home, found out cylinder farthest from fuel tank had no compression took it apart and had a hole in the piston.

    I assumed it was probably running lean because of the stock fuel pump, i had bought new piston and put it back together also upgraded the fuel pump to 3 outlet 780 pump. When i got engine back in craft just to test start it, the engine fired right up.

    Then when got inside, i had read that crank index can be off and cause hole in piston also, and this engine did have a little water in the crankcase could it be off? two outer pistons aren't at same spot when engine is turning over one is higher than the other. What do i do if the crank index is of? please help new with these 2 stroke engines.

  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    near Toronto, Canada
    Welcome to the Hulk

    Info on how to check crank index is posted in the Tech section.

    Regarding the holed piston, the entire fuel system must be in good shape, not just the fuel pump. Have the carburetors been taken apart and rebuilt?

    Water in the crank case? That suggests possible rust on the crank shaft bearings, which would not be good.

  3. #3
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Cleveland OH
    Welcome to the Hulk.

    Many causes for the dreaded holed piston.

  4. #4
    Okey ill go check it out . If it is out of index what do i do?

  5. #5
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Cleveland OH
    If it's out of index, you need to remove it and ship it to a crankshaft specialist. There's nothing you can do yourself about it.

    First do the index test.

    Then do a leak down test.

    If both of those pass, then check out the entire fuel system.

    This and the links in K447 sig will help you out with many Q's you may have.

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