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yfz 450 piston in 1/2

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Quad
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PostPosted: Thu Oct 15, 2009 11:01 am Post subject: yfz 450 piston in 1/2 Reply with quote Back to top

just asking has any other people had this .

trying to race and motor stopped .

found that the piston was in 2 ,clean brake throught the pin.

is this normal for a cp piston. for about 10hours or less.
 
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4stroker



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PostPosted: Thu Oct 15, 2009 1:36 pm Post subject: Reply with quote Back to top

show us!
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YFZ 450 White bros
90cc 2 stroke / 110 4 stroke


Joined: 10 Nov 2008
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PostPosted: Fri Oct 16, 2009 10:33 am Post subject: Reply with quote Back to top

i split my standard piston... just came into a corner, low revs, and she stop running, ended up having to get a new barrel.

was very different, i have heard from it happening on the yfz's a couple times too.
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Quad
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PostPosted: Fri Oct 16, 2009 5:27 pm Post subject: Reply with quote Back to top

Yes common on the JE pistons as well this one 96mm
 
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JONO
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Joined: 27 Sep 2007
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PostPosted: Sat Oct 17, 2009 6:17 pm Post subject: Reply with quote Back to top

Quad wrote:
Yes common on the JE pistons

Thats a bit of a generalization, i wouldn't have thought splitting JE pistons in half would be a common problem otherwise they'd realize they were doing something wrong and change it.
 
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PeteW
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Joined: 09 Feb 2006
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Location: Doreen, Vic

PostPosted: Tue Oct 27, 2009 8:46 pm Post subject: Reply with quote Back to top

I have seen a fair few break but only on the older motors (up to 06) both JE and CP's cracked right through, usually 13:1 pistons that go (GYTR used to do the same)
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4stroker



Joined: 15 Jan 2007
Posts: 1420
Location: North Queensland

PostPosted: Wed Oct 28, 2009 9:49 am Post subject: Reply with quote Back to top

if they all do it then it mustnt matter what they are made out of or how they are made, it must be to do with the skirt length or something? or rod ratio on the older motors?
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gazman
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Joined: 08 Jul 2007
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PostPosted: Thu Oct 29, 2009 3:30 pm Post subject: pitons Reply with quote Back to top

pistons don't usually just "break in half".The pistons in most modern bikes have very little below the pin to stop any slap. 13:1 comp sounds like a lot for unleaded,let alone leaded fuel and it is a biggish bore also.(they are prone more to detonation.)R u sure the engine is not detonating(pinging)?
 
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DON450
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Joined: 21 Jul 2008
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PostPosted: Sat Nov 28, 2009 6:44 pm Post subject: Reply with quote Back to top

my je did the same!!!
 
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