G'Day Guys, I'm having a few hassles getting my jetting perfect. I have looked at the jetting database and done a lot of jetting in the past but I reckon this may be better answered by someone who has been there before. It's an 05 WR450, needle from the spares kit supplied (not the single clip position needle), standard exhaust with the restrictor and spark arrestor removed and a larger diameter tail pipe replacing the standard pea shooter, 170 main, 48 pilot and the rest standard jets. I have the YZ throttle stop, done the air cut mod blocking the vacuum port, disconnected the grey wire and removed the intake snorkel. I've done a full throttle plug check and it looks perfect, the bike starts easily, warms up on the choke, then idles a little roughly without the choke about 2 - 3 minutes after starting. When it's fully warmed up, pulling the hot start raises the idle slightly (suggesting the pilot is rich). When hot it starts without the hot start (suggesting the pilot is lean). It backfires when I back off at medium to high speed (suggesting lean pilot), I need to adjust the fuel screw and idle speed often to get a stable idle and when at higher altitudes the idle is more unstable often hanging up high (suggesting the pilot is rich). The biggest problem is climbing slow, twisty, slippery, not so steep hills where you need constant but small (1/4 to 1/2) throttle openings. The bike surges making it tiresome to keep on track. It has no problem blasting up really steep hills at larger throttle openings. It feels lean to me but I was wondering if you guys have experienced this and how you fixed it. Usually surging and popping like this happens when a bike is lean but the higher idle when the hot start is pulled in and getting worse at higher altitudes stomped me. Wodyareckon?