Jet Setting Question

4 replies to this topic
  • johncook426

Posted July 26, 2009 - 10:42 AM


I just bought an 01' 426 and did the 450 auto decompression modification and it has a pro circuit T-4 exhaust system. Im not sure if its jetted right for my elevation which is between 4000-5000 ft. Im not sure if by changing the cam the jetting needs to be changed because the head pipe from the engine is glowing red after a couple minutes at idle.. Any help would be greatly appreciated as I am very anxious to ride this beast... THANKS!

  • grayracer513

Posted July 26, 2009 - 10:53 AM


Refer to Fuel Systems in the Common Threads Sticky, located on the index page for this forum.

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  • johncook426

Posted July 26, 2009 - 04:53 PM


did not see one that would be the same as mine as far as elevation or with the cam mod.. If anyone can help. I'd appreciate it...

  • grayracer513

Posted July 27, 2009 - 11:49 AM


The cam mod will have no effect on jetting. Find one as near your altitude as possible, and adjust your jetting about 2% for each 2000 feet of difference (leaner if you are higher, richer if you are lower).

Then, read the rest of the jetting info in Common Threads, specifically, How to Confirm Your Pilot Setting, and the Guide to Jetting.

  • mjw1

Posted July 27, 2009 - 02:10 PM


Does the bike backfire on deceleration? My bike used to glow red like that until i put a bigger pilot jet in.

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