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  1. #1

    Piston Sizing question

    The Ski I purchased had a goofed up Mag cylinder and the other two are punched to 1.00 as stamped on the pistons. I purchased a parts ski that has a bad PTO cylinder, and all the pistons are stamped W7A, which I have read mean standard. If I put a standard cylinder and standard piton in the mix with my 1.00 pistons, am I asking for a catastrophe?

  2. #2
    ph2ocraft's Avatar
    Join Date
    Apr 2006
    Campbell, Ca.
    I've done worse.
    Have you found what took the cylinder down in the first place?

  3. #3
    He burned the piston due to the old fuel pump going bad. He changed out the pump and changed over to the mix. He just honed out the cylinder and stuck in a standard sized piston. It just slapped it silly.

  4. #4

  5. #5
    Click avatar for tech links/info K447's Avatar
    Join Date
    Jul 2007
    near Toronto, Canada
    Quote Originally Posted by friscoboater View Post
    ...If I put a standard cylinder and standard piton in the mix with my 1.00 pistons, am I asking for a catastrophe?
    Let me preface this by saying I am not a Fuji engine expert.

    That said, I wouldn't worry about it. It's a Fuji 750 engine, and you are not dealing with big power or RPM.

    Some guys really prefer to balance all three cylinders with the same overbore. Others seem to get away with mixing and matching whatever.

    The only part of the engine that is really going to care would be the crankshaft. You might have a little more vibration than if all three pistons were balanced weights, but I doubt it will be an issue.

    If the connecting rod big end bearing is good, and has not accumulated any metal debris from the prior piston failure, I would say just run it with whatever piston + cylinder you can find in good condition.

  6. #6
    Thanks for the info guys.

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