need help with wiseco piston install

5 replies to this topic
  • 2000yzf426

Posted May 08, 2005 - 06:08 PM


I've spent most of the day rebuilding my 426 after getting it back in pieces from a theft recovery. Needless to say its been quite the experience figuring what goes where and now I'm trying to install the wiseco hi-comp piston with a three piece oil ring and I'm not having any luck getting the damn thing in, the middle ring keeps poping out and to me it looks like the 2 outer rings are supposed to hold it in. If anyone has some pointers that would be great.

  • FFRacing79

Posted May 08, 2005 - 07:27 PM


The easiest way to install the piston is to do it on the bench...then with the piston and cylinder together, install on the motor. Tdub

  • grayracer513

Posted May 08, 2005 - 07:30 PM


They are supposed to "hold it in", as you say. At least, they are supposed to sit on the little ledges of the expander (the middle ring). The ends of the expander are also supposed to be butted. The truth of the matter is that the expander is supposed to hold the rails (the upper and lower rings) out. A ring compressor is an invaluable help with this. See if you can borrow or rent one.

Triplex rings are hard to work with otherwise, and although it is possible to assemble them without a compressor, it's also very easy to damage the ring doing it that way.

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  • FFRacing79

Posted May 08, 2005 - 07:32 PM


GR, try it my way if you haven't is so much easier. Tdub

  • grayracer513

Posted May 09, 2005 - 06:35 AM



I do that when possible, but not all of the YZF cylinders are cut out on the sides, and the oil ring is so close to the wrist pin that by the time the piston's low enough to put a pin it, the rings are back out. I figured his '00 model would be like that.

When I do them on the bench, I use a compressor and put the piston in from the top.

  • 2000yzf426

Posted May 09, 2005 - 04:50 PM


Thanks for the info, tomorrow my buddy is bringing his compressor in to work so i should be able to get it done with that.

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