Stock Jet sizes for '99 220

Joined
May 7, 2007
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#1
Hi all, I gritted my teeth and dug into my carb today. This KDX is my first 2 stroke dirt-bike and I was not happy with the throttle response. A quick check of the plug revealed that the bike was running pretty rich. I read the tech tips on the Just KDX site and headed out to check my jetting.

With an FMF pipe/silencer and airbox lid removal, the site reccomends a 145-148 main jet and the stock needle in the second slot from the top. My bike has a 150 in it! Dropping the needle and tweaking the low-speed air-screw seems to have brought the bottom end to life.

Does anyone know what sizes of low-speed and main jets a '99 220 would have come with? When I change jets should I just go down one size at a time? Can I compensate for what seems to be an overly large main jet by dropping the needle farther?

Thanks for your help!
 
Joined
Nov 9, 2004
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#2
I was lazy with mine and just blindly put in what I read that I should put in and have been happy with the results. But to answer your questions...
1. I don't know
2. You can go down one at a time or just put in the 145 or 148 and 2nd from the top on your needle.
3. NO. They affect fuel rates at different throttle openings.
I would recommend using what you have read. Good Luck!