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  1. #1
    "Live life to the fullest, no one gets out alive" prunyon's Avatar
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    SLX780 Engine overhaul

    Hey guys,
    I got some great advice over on pwctoday form some great guys here. I am in the process of rebuilding my SLX. I pulled the heads and found out that the PTO carb was burning way too lean, and burned up the piston. The connecting rod is toast as well. The question I have is has anyone ever replaced the lower connecting rod, pin and bearings? Is that possible using a hydraulic press? Money is an issue here, and I am trying to get this engine back up and running for this season and buy a rebuilt engine at the end of the year, so I am trying to replace as few parts as I can. I have a clymer's manual, but no help with that part.
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  2. #2
    Jug Inspector
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    If you have the right tools and patience you can perform your own crank rebuilds. The problem is that the correct tools cost a total of around $1000 ... cheaper in the long run. I'm halfway there (just need a truing stand and a seperator)..but not worthwhile for a one-timer. Your best bet is to find a used crank from here or Ebay and toss it in.

    That PTO looks more like foreign matter got into it rather than a lean burn down.. maybe bearing pieces or a screw. Either way I'd be concerned with the whole thing running leaning looking at those wash patterns (or lack thereof!)

    Bryan

  3. #3
    Jug Inspector
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    Post a pic of just the PTO piston from above, like a bird's eye view. Usually when a cyl starts to lean out the exhaust side will get hottest fastest causing that portion of the piston to start melting and kind of dripping down the side and I don't see that on this piston.

    Bryan

  4. #4
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Not advisable to try on your own. Like he said ^^^^^ look for a used one to buy or send yours out for rebuild and use it when you do the engine at the end of summer.

  5. #5
    Connecticut CrazyA's Avatar
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    I'd be willing to bet money that the lower rod bearing is the cause of this damage. Grab that rod and pull up and down.... you'll know if it's it.

    Let's see some pics of the head. There's probably needle size impressions in it.


    .

  6. #6
    "Live life to the fullest, no one gets out alive" prunyon's Avatar
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    CrazyA,
    you were dead on! I pulled the cranckcase out, took the pistons off, and dang! The lower connecting rod bearing is completely GONE! I know SBT is offering rebuilt cranks for about $375, does anyone know of anyone doing them cheaper? Or possibly has a decent used one? Or where can I send mine to be rebuilt?

  7. #7
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    $375 is the cheapest you will ever get for a rebuild. Many places to send it too for repair, but will cost almost $500. Check Ebay for a used crank? PS: good call CRAZYA!!!

  8. #8
    "Live life to the fullest, no one gets out alive" prunyon's Avatar
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    Decided to go with a re-man SBT engine

    Well after much deliberation, I decided to buy a premium engine from SBT. It will be here Thursday. Now the question is, to block the oil pump and pre-mix or not to. I am tempted to, as to prevent this from happening again, but I am not positive it was the problem to begin with. Do I need to cap the oil lines going to the carbs, i am assuming so. Also, can I leave the carbs to the factory settings? One more thing, I have to install the stator, flywheel, etc on the new engine which means timing! I have a timing light that I have used on cars, but not sure if this will work for the ski, and if not, do I have to buy a special one. Any quick tips on timing? I have done a V8, lol...

  9. #9
    Moderator beerdart's Avatar
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    The stator static timing is all that is required. At the 3:00 pos there is a line on the stator that lines up with the crankcase parting line. You can use a timing light to verify timing Thur the black plug on top of the flywheel housing.

  10. #10
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Quote Originally Posted by beerdart View Post
    The stator static timing is all that is required. At the 3:00 pos there is a line on the stator that lines up with the crankcase parting line. You can use a timing light to verify timing Thur the black plug on top of the flywheel housing.
    Splitting hairs again, but the line is at about 9:00. I think I've found out the part number differences between elec. stators for the Fuji. The line BD speaks of is in different locations for the 650, 750, and 780. The 650 has the lowest line on the stator plate, the 750 is 2mm higher, and the 780 is 2mm higher from that. So, the 780 is 4mm higher up on the stator plate than a 650. FYI:

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