Let me just start by saying that I DID search the forum, read the stickies, and did my homework in general about the subject. However, even after reading all of that I'm still having issues. Here's a little background info: 08 yz450f Elevation 500-2000 ft. temperature 50* Dr.D full system Just after I bought my bike I replaced the exhaust with an 06 stock silencer and a pro-circuit header. I jetted the bike with a 48 pilot, 1.5 turns on fuel screw, stock needle 3rd position(stock), and 162 main. It was running good with that combination. No backfiring, overheating , or excessively red header. It was pretty good with those settings. Now I have a full Dr.D system, with the above mentioned settings the bike would get very hot and it would shoot some flames from the muffler. I changed the settings to 45 pilot, 1 3/4 fuel screw, needle 4th position, and same 162 main. Now the bike is overheating pretty bad and drops coolant to the floor, it also gets an excessively red header and shoots flames with more than 1/2 throttle. I've read several threads/posts from other with the same bike/pipe and my settings don't seem that far off from everyone else. Any ideas?