Hi folks.. I posted this on the KTMtalk forum and got some great help, but I think I sort of exhausted the knowledge base there. I did a little searching here, but I can't find a solution.
On my 2000 KTM 520, I have a severe bog, it's just off idle. If I crack the throttle open I get a huge bog, easily enough to kill the motor if I leave the throttle open.
If I roll the throttle on, no bog, no hesitation.
Carb: Factory carb
AC pump cover: P-38 lightening
Jetting: JD jet kit RED needle, absolute MIDDLE clip
Main 172 (maybe 170)
Fuel screw is about 1.25 turns counterclockwise
Weather: Low 80s, very high humidity, elevation is 1200ft
I have checked the AC pump screen, it's clean and not full of "aftermarket" holes. The pump actuator rod begins moving with an imperceptable difference to when the throttle is activated. Squirt is appropiate acording to the KTMtalk guys, about a second or so. It's not a huge spray, but it easily leaves the carb throat.
I have changed the pilot from a 48 to a 50 and to a 42 (don't happen to have a 46) and that makes ZERO difference.
If I pull the choke, it helps the bog go away. But I am not really sure what that means.
Anyone have any thoughts on this? I am absolutely at wits end!! I am this ->||<- far from paying someone to fix it for me.