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Piston Ring Position

11325 Views 17 Replies 6 Participants Last post by  cmat
is it ok that the 1st compression ring gap is 120 degrees away from the 2nd compression ring gap??
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i put my motor together and i just want to make sure this is ok. It has a lot of compression
my top ring gap is around b and my second ring gap is around c and my oil rings are 120 degrees after my 2nd ring gap
That Cam sure is a helpful fella :icon_biggrin:
Did you say all your oil ring gaps were at the same spot?
If it's a custom or aftermarket HC piston, it should have a diagram of how to ring the piston. If not then I would at least follow the diagram that Sidewinder posted.

Your oil rings(the 2 seperated from the oil scraper ring) should not be alingned together.
Does anyone have a diagram on how to install a 97mm 13:1 cp piston
Does anyone have a diagram on how to install c-clips
use the one sidewinder put up
QUOTE (Sidewinder @ Apr 28 2009, 03:36 PM) index.php?act=findpost&pid=774764
i was just read another topic and i saw someone post this:

Most times when this happens the wrist pin breaks in two, or the rod and wrist pin break out of the wrist pin journal on the piston.

Then the next ones I've seen are where the rods breaks in two. The piston is lodged in the jug and the broken end of the rod rotates busting out the cases.

Was this a stock 08 crank and rod? With the 20mm wrist pin.

Back in the day the 20mm pistons used to snap wrist pins out of the piston wrist pin journal and so the WR conversions with the 18mm wrist pins became more popular. 18mm pins leaves more material on the piston to support the wrist pin. Not saying this is a better option... just some history.

It is possible that a wrist pin clip popped out leading to the wrist pin walking to one side before the pin ripped out of the piston journal. In this case you would want to see how the clips were installed and how they were indexed. I leave the wrist pin clip end gap at 6'o-clock, that way the forces applied to it will push the pin to 3 and 9 o-clock thus locking it in place. If the clip end gap is at 3 or 9 then the forces will collapse the clip leading to it popping out.

IMO... CSI it, and let the parts tell the story....

Keep us posted with the pictures.
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im going to be putting my motor together and i need to know whats the right way to install the c-clips
i also have another question does a local yamaha dealer sell valve shims?
They should be able to order them if they don't stock them.
Dont forget to check your ring gap, even on the oil rings. I have seen them overlap before.
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