Originally posted by SDRIDER15
MY GIRLFRIEND HAS A 2006 YFZ450 QUAD. AND IM HAVING PROBLEMS WITH GETTING IT RUNNING RIGHT. IT BACK FIRES A LOT AND WILL DIE OUT WHEN YOU PUNCH THE GAS FROM IDLE. IM GOING TO CHANGE THE JETTING TODAY AND WAS WONDERING IF I COULD GET SOME POINTERS.

*ENGINE IS STOCK
*K&N AIR FILTER WITH AIR BOX LID OFF
*STOCK PIPE WITH SPARK ARRESTER REMOVED.

I WAS GOING TO CHANGE THE JETTING TO 165 or 168 MAIN, 45 PILOT AND THE REST STOCK. WHAT DO YOU THINK THE JETTING SPECS SHOULD BE FOR THIS SET UP?

THANK YOU FOR YOUR HELP.
The jetting that you suggested should be real close. I would put the 165 in since you don't really have anything done except the K&N.