09 wr450 jetting 8500'

just got a new 09 wr450 did all the free mods, just wondering about getting the AIS GYTR kit? so what size jetting do i need for rideing at 8500', appricate the help thanks.

The jetting that comes in the GYT-R AIS Kit for 2007 and later WR's has been found to be too rich at sea level and out of the question for higher elevations by most riders. I ride a 2008 WR450F from sea level to 5,000+ft (most often 2,900 - 5,000+ft) and the stock jetting for the 2004 WR450f has worked the best for me. This jetting consists of a #45 Pilot Jet, OBDWR Needle in the fourth clip position, #165 Main Jet, #70 Pilot/Air Jet and the Fuel/Air Screw turned out approx. 1 3/4 turns or adjust for optimum performance.

This jetting is probably too rich for you, if you actually ride all the time at 8,500 ft. However, its a good starting point. If you go one size leaner on the pilot and main jet sizes that I listed here, you are going to be in the ballpark for 8,500 ft.

What you end up with in the AIS kit that is actually useful is the aluminum blank off plate, some rubber plugs that blank off the vacuum line fittings, the YZ throttle stop and the instructions for incorporating the "free mods" (i.e., disconnecting the grey wire, opening up the air box, removing the air box snorkle and removing the inner restrictor tube from the muffler).

Save your money by making a diamond shaped blank off plate out of .089 - .120 aluminum (use the diamond shaped flange on the AIS tubing for a shape template and thickness gauge) , cut your WR throttle stop to the YZ dimension (or buy YZ throttle stop), go to the auto parts store and buy the vacuum blank off plugs, buy OBDWR needle, buy the jets one size smaller than those I listed above (i.e., #42 pilot {slow} jet, #162 main jet and use the stock #70 PA jet) and read "sticky" instructions on this forum for "free mods".

Get some more advice from people who know what they're talking about. The Ais removal kit is way less than $100. By the time you add up gas, wear and tear on your car and your time not to mention some money for parts you could hit double on your cost!

Your bike comes with a 162 main jet and a 42 pilot. I ride in Vegas and Colorado. I have free mods and dealer installed AIS removal kit. I just moved back to Denver and re-jetted for higher elevation. I run a 48 pilot and a 172 main in Colorado with the needle in the third position down. I run a 50 pilot and a 175 Main in Vegas withe needle untouched. The needle is hard to move! I can change the jets and change my oil in about an hour. Play with the fuel screw until it runs good staying inbetween 1.5 and 3 turns out. Find a GOOD local shop and spend a few bucks there! They are a rescource you will need and it's a good place to meet like minded people! Good luck!


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