High altitude carb tuning 400f

3 replies to this topic
  • jagarcia89

Posted September 28, 2009 - 04:03 PM


My bike came from sea level so I jetted it to local shops recommendation, it now fires up first kick with a bit of gas but won't idle without the choke on or giving it some gas. I then turned the screw on the bottom out a few turns and it would idle for a little bit longer then die. So I figure I need to richen it up. My question is how many turns is it safe to go out on the adjustment screw because I went 7 before thinking it may be too far. Based on the change going from 3 to 7 turns, it seems I'd need like 10-12 turns. Given that I'm fairly confident that's too much, how much should I increase my jet size so I don't have that thing holdin on by a thread? And lastly where can I find a heatshield for this header??

  • grayracer513

Posted September 28, 2009 - 04:15 PM


What is your altitude?

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  • jagarcia89

Posted September 28, 2009 - 06:37 PM


Most riding is done at around 6000ft right now but would like to hit a few local trails that get to around 7000 if possible

  • grayracer513

Posted September 28, 2009 - 10:17 PM


Multiply the sea level jet sizes for the main and pilot by 0.94 and start with that.

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