I was troubleshooting my pilot circuit on my 2001 yz426 due to a little bit of a hanging idle condition, using alot of the tips on this forum. I could screw my fuel screw all the way in and the bike would not stall, which seemed to indicate that it was too large. My manual was marked up with a previous owners notes, and it indicated that the pilot was one larger than stock, which made sense. So, I decided to buy a stocker since it was less than $4. But, even with the hanging idle, it would start first kick about 19 times out of 20, hot or cold. I ordered and installed a new stock pilot jet. (turns out the pilot jet 'was' stock, but gummed up as I could barely see through it) I also replaced the throttle cables (since they were frayed) and the exhaust washer, which was missing. I think I have the throttle cable adjusted pretty good, and have a little bit of free play. I followed the manual as best I could, but with the way the throttle cable adjusts it seems like there is alot open to interpretation. With the stock pilot screw swap, the throttle cables adjusted and the exhaust washer in, I am having a helluva time starting it now. I checked the carb boot to make sure it is on tight, and have just done a basic once over. I have done some searches and know that tight intake valves could also contribute, but it was starting perfectly before the changes above. It is taking a minimum of 6-8 kicks now when it is cold, with the same starting procedure. (2 pumps of the throttle, and the usualy decomp lever process) It seems like it wants to start, and seems to turn over a few times but not stay running. It also seems to pop a little bit, and doesn't seem to be running any better than before. Any ideas on what else to check? I am going to try some carb cleaner to see if I have a vacuum leak somewhere and will also check the valves.