I bought a trashed '96 XR600 last year. It was trashed, but it got me through my yearly dunes trip with the guys. I put about 300 miles on it with no issues (other than an oil leak due to a damaged head and head cover). It also gave me time to put in a new top end on my other bike ('89 XR600). This spring I put in a new top end (.040 over 11:1 piston). I bought a used cylinder head and got a valve job done. I also purchased a used head cover. I replaced the head and cover because there was some damage to the front of the casting creating an oil leak. Upon disassembly I noticed the rocker was removed from the exhaust valve that works with the decompressor. The bike had been running with 2 intake valves and 1 exhaust valve. When I re-assembled the engine I set the rocker clearance without the decompressor cable attached, so it was set incorrectly. The bike started on the 3rd kick and ran fine, but a little rich. I had some obvious noise from that loose rocker. I set the decompressor free play to factor specs and adjusted that exhaust valve. With the 4th valve working the engine will hit and run for 1.5-2 seconds and it dies, no matter how much throttle I give it with the choke closed. It smells like it is flooding. I don’t get it to hit with the choke at 1/2 or open. It already had larger than stock jets (168 main jet and 52 pilot jet). Needle is in the 2nd to the bottom notch, which will make it more rich. Any suggestions???