Apr 6, 2000
Alright people, I've been riding KDX's for a few years now and pretty much have been able to come up with a solution for just about any problem I may have. Anyway, here's the deal...

I live near Chicago... Elevation, I don't know... Temp around 80... Humidity ahhh... well... depends on the day.

Anyway, I've got a 00' 220 with the the carb bored, Boyesen Rad Valve, and all the motor mods done. (and FMF Rev Pipe).

Right now I'm running the needle in the Middle Position, 155 main, 42 pilot. I've been fighting my jetting for some time now, but the bike keeps bogging as a roll on out of a corner or on anything that is roughed up or inclined.

I really notice it when I've been riding at a mid RPM for a distance, then let off making a turn, then roll on out of the corner. It's like a "cackle" and then really goes on the pipe. I've tried just about every different combination from 42 - 48 pilot and 155 - 160 main. I haven't adjusted the needle at all.

The only thing I can think of is the Power Valve is getting gummed up... if anyone has an other suggestions comments, please mention anything it might be... this has been going on for like 2 months now!


die you sycophant !
May 22, 2000
Summertime blues!

Warmer temps tend to richen the jetting as the air is less dense. What works great at 55 will be ugly at 85.

If it stutters or 4 strokes as you begin to open throttle and then smooths out as the load increases you are jetted rich. from your description it sounds like either the pilot or the needle in your case. I would try a 42 pilot then try dropping your needle a clip positon or 2. You might be a little rich on the main for your temps but you shoulld run a plug chop to find out.

Remember, change one thing at a time.

Hope that helps and have fun riding:)


dirtbike riding roadracer
Mar 28, 2001
Have you checked to see if the reeds are cracking? I had my rad valve crack a reed and it had the same problems.

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