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Thread: JE pistons?

  1. #1
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    4th December 2006 - 10:27
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    JE pistons?

    Just bought a top end kit for my RMZ450 off Trade Me it's a forged JE piston ups the compression ratio is it correct that these need no jetting just install and ride? Goes from 11.9 : 1 to 12.8 : 1 don't want to blow it up!!!

  2. #2
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    3rd April 2008 - 21:32
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    You will probably have to re-jet

  3. #3
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    14th August 2007 - 19:42
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    Secondfield has a JE in his 05 RMZ450 and hasn't touched the jetting, his piston increased the comp. ratio but i don't know by how much, PM him, he'll be happy to help. It will be fine just run it

  4. #4
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    9th January 2006 - 12:26
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    i went bigger on the main jet when i upped my compression in my 06 rmz450,

  5. #5
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    26th December 2007 - 10:09
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    Stroke and displacement remains the same - however if compression ratio rises I would suggest higher octane fuel to prevent pinking or pre ignition - 96 or 98(which you probably use anyway) What does the Suzuki manual suggest you use?
    Whether you think you can or cant - you will always be right.


  6. #6
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    Quote Originally Posted by scott411 View Post
    i went bigger on the main jet when i upped my compression in my 06 rmz450,
    I was going to suggest higher compression prob means more heat and a bit more fuel might be the go.
    Definatly see how its running and have a fiddle anyway?
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  7. #7
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    4th August 2008 - 15:33
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    Mine worked out sweet, it does run a bit richer ive noticed though ... installed a fuel screw while i was at it. Stock jetting with the screw wound right up (lean as) and its still running a bit rich. Gonna change the needle position in the carb, running the bike on BP98...
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  8. #8
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    26th December 2007 - 10:09
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    Quote Originally Posted by secondfield View Post
    Mine worked out sweet, it does run a bit richer ive noticed though ... installed a fuel screw while i was at it. Stock jetting with the screw wound right up (lean as) and its still running a bit rich. Gonna change the needle position in the carb, running the bike on BP98...
    Sounds good. What about running temp - same?
    Whether you think you can or cant - you will always be right.


  9. #9
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    4th August 2008 - 15:33
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    Yep, I wouldn't be 10% sure without a temperature sensor ... but I have had no issues with it boiling in the tight nasty stuff, runs cooler than my old exc400 did. Tommorow will be the test - links track in karipoti ....
    For REAL news (instead of that shit they spoonfeed you every day on TV) go to - http://www.openureyes.org.nz/blog/

  10. #10
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    20th September 2008 - 16:54
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    JE Compression

    JE pistons can run higher than stock with std jetting it is the way the crown is designed and squish area good piston manufacture knows what they are doing not like a cheap made stock cast design pistons and also it is were the rings a placed to transfer the heat from the piston to the cylinder to the water jacket JE has a lot better ring area, www.motoxparts.co.nz
    and we have 25 years machining building performance engines.

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