i have an 05 yfz450 quad. just threw the chain, and cracked the case. my buddy has a set of cases off an 06. one guy is telling me they will fit, and another is telling me that 04-05 is different than 06-07. before i rip this motor out, does anyone know for sure?

 

anyone?

 

I think they changed the CC's somewhere in that time frame, but i don't think that would affect the case any. So i think it would work.

 

i know for a fact it's the exact same piston

 

the mounting bolts look like thay match up with the frame too. i'm just afraid the guts won't match up

 

As far as I know they are the same

 

<div class="FTQUOTE"><begin quote>Originally posted by: markymark116

i know for a fact it's the exact same piston</end quote></div>

Yamaha upped the displacement from 439cc to 449cc in '06. I would think they did that through bore but, it is possible the stroke is different. Either way that is something to watch for.

 

just look it up on an OEM page and see if when you go to order the cover if it has the same Part #.

 

If its the same piston, then the stroke is different, and that could cause you some issues

 

Yamaha increased the displacement in 2006 by stroking the crank by 1.4 mm- All the 2004/2005 parts will fit in the 2006 and later cases- you can also install the 2006 and later crank and piston ( same as the 2004/2005) into the 2005 cases-Yamaha has superseded the 2004/2005 case numbers with a 9999 series number which are the same as the 2006 and later cases- I just bought a new set of cases from MR Cycles for $258.00- Make sure you do the 2007 oil squirter mod which will save your crank and rod on the 2004/2005- I found out the hard way -$1500 worth of parts later!!!