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Stumped 09 kx250f dies runs poorly

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I have a 2009 Kx250f monster edition that I purchased preowned a few years back. Third ride on the bike I dropped a valve and cratered the cylinder head. Purchased and installed a brand new factory Cyl. head and valve train (excluding cams) installed all new parts, 5 rides at the track the bike was running like a scolded ape, 6th ride I landed off a100ft table top, gassed it on landing then hard on brakes for next turn, the bike died when I pulled the clutch in, took me over 5 minutes of kicking to get it restarted and once it started it was backfiring and died 4 times on the way to my truck... ever since it runs like hammered dog poo. I've pulled the carb off 3 times and cleaned it, pulled cylinder head to check valves, reshimmed valves, checked timing, tested all ignition components, compression is spot on. Even had a shop rebuild the carb just for good measures. No matter what I try this thing will not run properly. It will run on choke (barely) but will not idle off choke, which leads me to believe the pilot circuit is clogged.. but 4 carb builds later in an ultrasonic cleaner should have done the trick. I'm stumped, anyone out there have similar issues or any insight on what to try next? Any and all help is greatly appreciated. 

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To me, this sounds like these possibilities;  1) fuel system dirty, pilot circuit restricted by something.  2) an air leak such as; loose clamp, crack in carb to head boot, leaking connection or stuck hot start plunger. 3) a slipped camshaft sprocket, where the sprocket has spun on the camshaft and the cam is actually out of time regardless of where the dots are set when checked.

 

Edited by FaceDeAce

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