1996 CR250 carb. adjustment / jetting ?

Joined
Apr 29, 2002
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#1
Alright, I have a dual stage Uni filter, no airbox lid, and an FMF PowerCore silencer. I had it jetted and it ran PERFECT, never fouled a plug. Well, last year I added a set of Boysen Power Reeds and had it re-jetted again, but I don't believe they really messed with it at all, which is why I do everything myself now. It was running rich so I had planned on re-jetting after I got my FMF Fatty installed, but was told the pipe would lean it out some more so I've been running it with the pipe on, with no problems. Runs like a bat outta hell. The plugs / porclin are just really dark / black and sooty but dry and I replace after about two days riding.

This past weekend I bumped the clip on the needle up two notches to the very top. I run Blendzall and 92 octane @ 32:1. I spent yesterday at the track trying to get it to run right by adjusting the air screw...it was out 3/4 of a turn, and would bog when I went WOT. I corrected this by setting the air screw to 1/2 turn out, but it is very picky now. Less than 1/8th. of a turn either way and the bike bogs. I have yet to pull the plug to see how it's burning. Should I call it good or do I need to mess with something else?

My uncle got a "new" 2001 KDX200 last week and we installed a new FMF Gnarley Torque and FMF spark arrestor on it Fri. His was bogging too, so I adjusted his air screw from over 1 turn out, to about 3/4 out and his bike run perfect now and the plug has a nice tan color and line below the proclin the width of a pencil lead. I don't know much about carb. adjustment...how does the clip pos. effect the way the carb works besides leaning out the 1/4 - 3/4 throttle positions, and how does the airscrew effect things? Thanks!!!

-AR
 
Joined
Apr 16, 2002
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#4
id give it a shot, my 96cr250 has the needle in the middle grove. mine is smooth as hell, what is yours like?
 
Joined
Dec 14, 2001
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#5
I agree about lowering the clip. Bogging is usually a sign that it's too lean. Plug colour can be misleading if you're not doing a proper plug chop. Better to set it where the bike runs best.