Need Help with carb at 10,000'

4 replies to this topic
  • Colorado426

Posted October 27, 2001 - 04:28 AM


Hey Guys I know we have a lot of threads on jetting but none are for 10 to 12,000' feet. I have an 02 426 that I run a 152 main, 149 pilot, 3rd clip from top on needle and 1 3/4 turns out on air screw and bk mod. This bike ran great until I put a new pipe on it but cannot get it dialed. It has a terrible bog from low to mid then cleans out and screams!! ANY IDEAS GREATLY APPRECIATED. THANKS

  • yzernie

Posted October 27, 2001 - 05:56 AM


<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:<HR>Originally posted by Colorado426:
I run a 149 pilot[/QUOTE]

Little confused on the "149 pilot". What kind of pipe? Most aftermarket pipe require richer jetting.

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  • Colorado426

Posted October 27, 2001 - 09:49 PM


Sorry its a 40 pilot and its a Dr. D pipe. Thanks

  • Scott_in_KC

Posted October 27, 2001 - 10:14 AM


I too would think you'd be going richer with that pipe.

Have you tried adjusting the pilot screw yet? Get a short screw driver (I use a long screwdriver bit from my drill set) and turn the screw out (loosen), this will make it slightly richer. Keep track of your turns so you know where you're at.

If you have some success either making it richer or leaner with the screw you might try raising (richening) or lowering (leaning) the needle one clip too. The clip has huge effect on that mid range bobble that will develop from being to rich or lack of power from being too lean. One clip can make a BIG difference!

I found my WR to be very sensative to a pipe change and actually went leaner with a more open YZ pipe vs. the stock restrictive WR pipe...go figure. So sometimes it's not always as it appears.

  • Colorado426

Posted October 27, 2001 - 01:44 PM


Thanks so much for the help. I turned the screw out 1 more full turn and the thing runs perfect!! Thanks again for the help.

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