YZ450F compression?

9 replies to this topic
  • JIMTED79

Posted March 09, 2007 - 10:50 AM


Want to get a new top end and want stock compression does anyone know what that would be for a 2004 YZ450F?

  • flintlock28

Posted March 09, 2007 - 11:05 AM


The stock Yamaha is considered to be of very high quality, also Wiseco is a good piston also. I think stock is 12.5:1, but not positive.

  • vpmx

Posted March 09, 2007 - 07:04 PM


You are right about 12.5:1 for the 2004 model. Yamaha lowered it to 12.3:1 for 2006 and 2007.

  • mycrx

Posted March 09, 2007 - 07:06 PM


why did they lower it.

  • mycrx

Posted March 09, 2007 - 07:07 PM


my buddy has a 06 and my 04 hands it the 06 its ass everytime we race.

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  • grayracer513

Posted March 09, 2007 - 07:13 PM


So his is completely stock, and you drag race, right? :applause: That won't work with my '06.

Try this: ride his bike for 15 minutes, then roll off 3 timed laps. Then compare that with your best three on yours.

  • tmauto69

Posted March 10, 2007 - 06:24 AM


See I had an '04 and my '06 at the same time and the '04 seemed weak compared to my '06 when jumping off one to the other.

  • battle

Posted March 10, 2007 - 06:27 PM


Yea my buddy has an 06 and it hawls ass he ends up always faster than my 04 must be the 5 speed :applause: :lol:

  • yamaha racing 230

Posted March 11, 2007 - 05:44 PM


i heard they lowed the compression for less of it midrange hit. :applause: :

  • grayracer513

Posted March 11, 2007 - 07:52 PM


You heard wrong. The drop in compression was the byproduct of changes made to the combustion chamber to improve the head. A 0.2:1 drop in compression is inconsequential.

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