This is a basic tutorial on how to adjust the valves on the YFZ. Step 1: Remove front plastics and gas tank. [attachment=5334:pic1.jpg] Step 2: Remove ignition coil, oil tank breather hose and cylinder head breather hose. [attachment=5335:pic2.jpg] Step 3: Blow out cylinder with compressed...

So after everything I've done so far to try and fix this bog hasn't worked. Pipe, Dyno, PCV, yelling @ Yamaha, nothing. I've been hearing a lot of people rave about the Vortex and how it absolutely eliminates the bog. I have seen a lot of members out here saying their 14 is bog free using the...

picked up an 03 660 raptor and the guy said it runs fine and it does but you need to have the choke on all the time for it to run... then sometimes it sputters and dies when shifting gears. when you turn the choke off it completly dies and has a hard time starting sometimes. i took the carbs off...

Please post your jetting on your big bore stroker setups. Dyno #'s if you got'em. 2004 yfz450 490cc with a +4.4mm hotrods crank 97mm cylinder works 12.5:1,mild porting, steel valves, hotcams stg 3 i&e, stock 39mm carb, ziptie mod, stock cdi, 4.5" airfilter adapter with stock intake tube and...

This is a pretty basic outline for jetting on the YFZ450. These settings are for sea level if you are anywhere from 1500ft to sea level these settings should be very close to right on. Anything above 1500ft should lean the settings accordingly. Also, as a good adjustment you should raise the...