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  1. #1

    rebuiding slh engine question

    Hey guys. Just about to start rebuilding the top end on my slh700 engine. Do I just fit the new cylinder base gaskets or should I smear some non hardening instant gasket onto the new gaskets for peace of mind? Also any tips and hints that might come in useful when rebuilding the top end is greatly appreciated. ( fitting new pistons, rebored cylinders, new exhaust riser pipe, recon carbs, reed valves etc etc). The engine is also still in the hull so its a bit tricky to work around. Also my old riser pipe cracked internally! Is it a common fault? Just spent a small fortune on parts so it better go better this time!!


  2. #2
    thester71's Avatar
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    I used 3bond 1211 on my 750 base gaskets and when it had to come apart again it was a pain in the ass, I installed the base gaskets on my 785 and 1050 using a light film of marine grease, but they can be installed dry.
    Did you have a machine shop do the boring? If so did they use your new pistons to set the piston to cylinder clearance according to polaris specs? Also you will need to check the end gap on your new rings. I use the same 2 stroke oil I plan on using in the ski... as a lubricant when installing the new top end.

  3. #3
    john zigler's Avatar
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    i always install all gaskets dry, and clean.

    make sure, the machine shop chamfered your ports on your cyls.

    also be very careful to not break a ring when installing the cyls. it is difficult to do while the motor is in the hull.

  4. #4
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    As mentioned, gaskets do not require any sealer. Some stock base gaskets do have a nice bead of silicone to help seal them. So if you're using stock gaskets, prob shouldn't. Aftermarket gaskets don't need any either, but if it makes you feel better, go right ahead. Just use a very thin film of it. You don't want it oozing into the openings and and casuing problems.

    As mentioned, were your pistons sized to the cyls when bored? Make sure to check/adjust the ring end gap prior to install.

    Make sure your wrist pin circlips are installed in the correct direction (see piston install directions) and that they are 100% seated in the groove. Failure to do either of these may lead to piston and cylinder damage. Double check that the clips are fully seated.

    A good practice is to temporarily install the exh manifold (without the gaskets) prior to torquing the cyls down. That will properly "center" your cyls and prevent any possible gasket leaks/bolt misalignment.

  5. #5
    Thanks guys. Good tips! Not sure if the pistons were sized to the rebored cylinders. Im sure they will be as it is a polaris shop that did the work for me. I take it you dont just clip the wrist pin circlips in any old way?

  6. #6
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Did the machine shop have the pistons when they bored your cyls?

    Wrist pin circlips must be installed a certain direction.

    If you bought WSM pistons, follow their install instructions. If you bought OEM pistons, follow the manual.

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