Fuel Screw and Altitude

I finally got around to installing a Zip Ty fuel screw and #50 pilot jet on my Canadian model 03 WR450. I'll post my info on the jetting database once I get the bike out for a few hours of riding.

Right now at 1 3/4 turns out on the fuel screw, the throttle response is much better and starting is easier. (1500ft) :thumbsup:

My question is: which direction do I adjust the fuel screw when I go to higher altitudes?

I realize that I will only get some improvement without changing the jets for altitude. Used the search engine, but couldn't find the specific info on which direction. In or out?

Thanks.

Higher and hotter -- screw in (less fuel-leaner due to the air is less dense)

Lower and cooler -- screw out (more fuel-richer due to denser air )

WR Dave.

Higher and hotter -- screw in (less fuel-leaner due to the air is less dense)

Lower and cooler -- screw out (more fuel-richer due to denser air )

WR Dave.

Thanks for the input.

In a few weeks I'll be up in the mountains at around 7000ft. and will turn the fuel screw inwards 1/4 turn at a time (If needed) and see what happens.

If you are going to that altitude you will need to drop your pilot size a few #'s as well as your Main jet size. I run in those altitudes quite a bit and am using a 40 pilot and a 165 main with the YZ needle on the 3rd clip position. WR Dave

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