crf 450 carb tuning 2003


7 replies to this topic
  • ollacolla13

Posted October 20, 2011 - 08:54 PM

#1

having problem tuning my carb... yes i have read the manual.. the jets are right, valves are good.. still having trouble starting... needl is third from the bottom and pilot air screw is 1 3/4 turns out... and don't know about the air screw but it was turned way out... thats how i tuned it to low down the idle when i got it started... will start fine when its hot... in the manual it says 5th position for the needle and idk if its from the top or bottom... please help a little thanks

  • fxrs

Posted October 21, 2011 - 02:29 AM

#2

are you using full choke and 3 twist of throttle

  • tjg53

Posted October 21, 2011 - 03:48 PM

#3

Your poilt jet mite be getting clogged. Try a new one , and see how it acts. Over time they do get clogged with varnish.

  • 450XJimDirt

Posted October 21, 2011 - 09:20 PM

#4

I am gonna agree with tjg53 , your pilot jet is clogged , thank the Ethanol for that

If you have the proper jets for your altitude , and you read the manual and set everything to the recommended settings , then its either old/bad gas , or your pilot jet is clogged

  • ollacolla13

Posted October 22, 2011 - 08:49 AM

#5

in the manual it says for the needle position to be on the 5th spot... does it meet the 5th position from the bottom or top?

  • fxrs

Posted October 22, 2011 - 09:08 AM

#6

i would say from the top because it richens fuel you move the clip down

  • skthom2320

Posted October 22, 2011 - 12:04 PM

#7

Needle clip position is counted top down. +1 on the recommendation to just switch out the pilot. That is a classic symptom for a clogged pilot (or fuel screw too far in).

BTW - there is no air screw. The fuel screw on a FCR carb is letting in more or less fuel in the pilot circuit , not air.

  • ollacolla13

Posted October 23, 2011 - 08:07 AM

#8

my bad i meant fuel screw... i'll try a new pilot and see whats going on with that...





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