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  1. #1

    weisco piston to cylinder clearance

    So, who here has had any luck with these in their skis? What is the best clearance for these to be set at? I have heard of guys doing.007 but the specs are to be set at .004. .007 seems a little sloppy and my machinest said he has done them at that too for some local shops just to ensure that there would be no cold seizure issues. I also talked to the guys at Group K... they said to set them at .004 to .005, so I am still not sure. I will probably set them at .005 but is the colder waters here in the north west gonna affect the temp of the motor to warrant a different setting here?

  2. #2


    Go a full .005 and let it warm up good (cylinders before blasting off)I have run over 600 sets of wiseco pistons in rebuilds on the larger pistons like 951 seadoo and 1200 kawa or polaris I run .004 to .005 I build a tight engine, .007 is too sloppy.I know a few shops build them sloppy to keep from having a sezed engine from customer who wont break it in properly.but .005 is plenty even here in east texas ,its all in ring end gap, chamfering ports,and heat cycling it for 3 times before running it in water to take some tension out of the rings and seat them.set end gap to .010.use 50 to ! extra break in oil beside pump, and first start it for 15 to 20 seconds no water, let cool completely, do this again ,going 15 to 20 seconds at fast idle blipping throttle to clear engine,let cool do it one more time let cool and take to water start it up and break it in without lugging engine but no full throttle across the lake blasts until you have a couple hrs on it.from then on ride like wildman you wont hurt it,as long as you keep fresh fuel and oil in it.Wiseco builds some of the best pistons ever made>Marvin

  3. #3
    Thanks Marvin for the reply. I am glad you answered. Oh so I am not running oil injection. Will 32 to 1 be a good ratio? I plan on using Maxima Super M for my oil.

  4. #4
    Let it all hang out I Ride Naked's Avatar
    Join Date
    May 2007
    South Windsor, CT
    32 to 1 sounds a little rich, but for break in its ok

    Once it is broken in I would run 40:1 or 50:1

  5. #5

    Join Date
    Sep 2006
    i would use a 40:1 when breaking it in , one half of me says use the 1:50 the othere half says use the 1:30

    you wanna use less oil to break in the rings , but you wanna keep the bearings happy so meet them both in the middle ,

    alot of guys use this method of breaking in skis

  6. #6


    40 to 1 with our oils that are now available then 50 to 1 ,with premix its exact so 50 to 1 is greatafter break in(wiseco calls for 50 to 1 for break in ,one thing I never break in an engine with wisecos on sythetic oil,four stroke or especially 2 stroke, they dont allow enough wear for break in,use a quality two stroke oil until its broken in then use the best oil you can get!!!>Marvin

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