yfz piston

[Glenyzracer25]

i have an 06 yfz and am getting ready to rebuild it. i know the 06 are the class legal 450 and the 04-05 are only 439 with a 1mm longer stroke being the difference. are all the pistons the same or is there a difference. i have seen some companys advertise piston for 04-07 and others just 04-05 and a different piston for 06-07. im going to bump up the compression, probably 13:1 possibly 14:1, or is that to much? i already run a mix of race fuel, but ill being running straight 110 after the rebuild.

04-08 all use a 95mm piston with a 20mm wrist pin. So all pistons should work. a 14:1 is pushing it. You might need to do ring changes more often. id stay with a 13:1 for the reliability of it.

[Glenyzracer25]

thanks

[WOLFPACK]

CP makes a three ring piston that we've had real good success with.

CP is the way to go by far. velocity makes a awesome 13:1 cp piston. It a little better then the std shelf cp piston

[KENNY HEMMINGS]

Originally posted by Glenyzracer25
i have an 06 yfz and am getting ready to rebuild it. i know the 06 are the class legal 450 and the 04-05 are only 439 with a 1mm longer stroke being the difference. are all the pistons the same or is there a difference. i have seen some companys advertise piston for 04-07 and others just 04-05 and a different piston for 06-07. im going to bump up the compression, probably 13:1 possibly 14:1, or is that to much? i already run a mix of race fuel, but ill being running straight 110 after the rebuild.

JUST DONE THE TOP END ON MY 06, USED THE GYTR 13.1 PISTON
MADE A BIG DIFF.
WHEN YOU LOOK IN THE GYTR BOOK THEY SHOW 04-05 AND THEN 06-07 DIFF. PART #'S, I ORDERED PISTON KIT,GASKETS AND CYLINDER LESS THAN 400.00 AND GYTR ALSO OFFERS A DIFF.
GASKET SET FOR THE 13.1 OVER THE STOCK

[WOLFPACK]

If you look on the bottom of your GYTR piston it is stamped JE. JE makes a great piston!