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Discussion Starter · #1 ·
I have a 2006 yfz450 that i am rebuilding with a 97mm cp piston but im not sure what compression it is the guy i bought it from said it was 13:1 on a 2005 yfz450 but he said he wasn't sure but if it was 13:1 on a 05 then on my 06 it would be 12:5 and i would be able to run 93 octane and i was wondering how would i know if the compression is 12:5 on my 06 if im running 93oct will i hear a pinging noise, will it backfire or have a hard start if its higher than 12:5??
 

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well then if you dont know then we cant help you really lol. do a compression test.

if it was a 13.1 on an 05 it will be a 12.5 on an 06
 

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Discussion Starter · #12 ·
where could i get a burette and the box only has a the job # on it also how loud/noticeable will the pinging noise be
 

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not 2 be contradictive here guys (u should know more than me) but cp's site says that a standard bore 05 12.5:1 piston is a 12.75:1 on an 06

im looking into getting one thats y i thought id chime in
 

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Discussion Starter · #14 ·
the #'s for the 06+ cp pistons is wrong the 06 pistons. i thing the 06+ motors have a bigger combustion chamber and the rod is a little shorter making a 05 piston in a 06 .5 less
 

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dude what ur saying is that one of the top piston companies doesnt know what the REAL compression on there pistons is????
u sure dude??
 

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all the pistons are labelled correct for the 04/05 models. so whatever the catalogue list it as will be what it is

EDIT: damn i got beat again lol
 

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these guys are correct we all thought it was odd. Some one needs to contact them and inform them that they are dumb w00ters
 
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