Cinders Jetting

i have a 2002 cr250 and i am going to the cinders this weekend.... Stock main jet is 380. i currently run a 390. How many sizes do you think i will need to go down for the cinders. will i HAVE to change the pilot jet too.? ive heard you can get away with just the main.. I will only be ridding there one day and want to be as dialed as i can befor i get there so i CAN RIDE!! thanks alot!!! help!:thumbsup:

what elevation are you at now..... non one can help you with out knowing that.

but i would say as a general rule of thumb

on the pilot: 1 step down for every 3000 ish ft

on the main: 1 step down for every 2000 ish ft

when i say step i mean next smallest jet size, not 1 number lower

the relationship isnt linear either, the higher you go, the more the jet will need to be changed, like a logrithmic relationship.

like on a mian jet at 6000ft difference may require 5 sizes small not 3

id go back to stock on the main, and maybe 1 down on the pilot if at all. can use the airscrew too

this is a very rough guide, for 2t's

i live and ride in pohenix, so i guess i am sea level. like i said stock is 380 and i have my bike perfectly dialed in with a 390 main. dont remember the pilot but would guess its stock(what ever that is?) so with that info, what size main do you think i should go down to...? 350? 360? Lower???:thumbsup:

also arnt the cinders around 7000ft elevation.. so where should i be? THANKS ALOT AGAIN

i live and ride in pohenix, so i guess i am sea level. like i said stock is 380 and i have my bike perfectly dialed in with a 390 main. dont remember the pilot but would guess its stock(what ever that is?) so with that info, what size main do you think i should go down to...? 350? 360? Lower???:thumbsup:

also arnt the cinders around 7000ft elevation.. so where should i be? THANKS ALOT AGAIN

phoenix is no where near sea level. we are anywhere between 1200 and 1400ft. like i said i would put the stock main back in, and adjust the pilot with the air screw. its better to be too rich than too lean. you dont wanna seize a motor half way up a hill. you gotta remeber you are going to the cinders. if it were regular riding i would lean it out more, but in duny kind if stuff you need to run a richer main

anyone with a 2002 or newer cr250 go to the cinders and what specs are you at?!

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