So long story short my buddy has an 05 WR450 that hasnt ran right since he bought it. He bought the bike used with all the free mods done and an FMF pipe.First trip out it had battery issues, popped and backfired a fair amount and about 10 miles into the ride the fuel drain screw fell out of the carb. not a good start to owning a bike. since then it has gone through several more batteries (not the bikes fault) and been in the shop twice for it just running like shit and both times it came back running better but still not right and went back down hill after a ride or two. One shop said the cam timing was off and reset and the other rejetted the carb and sealed an exhaust leak. Now to the current issue. Bike has been sitting for about 2 months in doors since its last ride. Buddy has been busy with work and asked me to get it ready for our annual Glamis new years trip. Got the bike out and it was a BITCH to start and once it did it would not idle with the choke off. it never really has liked to idle with the choke off but it is worse now. i drained the gas and put fresh 91 in and it made no difference at all. pulled the carb (spotless inside) and went form a 52 pilot to a 55, again no difference at all. the fuel screw also make 0 difference, all the way in to 5 turns out does nothing at all. It will idle for maybe a minute once its warm but usually dies and while ride the throttle is very touchy with flat spots when under 25% throttle. it back fires and blows flames out the exhast occasionally and just all around runs like shit lol. carb seems clean, has what seems to be a huge pilot jet in it (55) and it still seems to be running supper lean especially when under 25% throttle. Buddy is now getting very tired of the bike, its been nothing but problems since day one and has left him sitting the desert. Im trying to get it running right for him before he sells it but im at a loss. We have never once had to touch my XR and the carb has never been off since we both bought our bikes used at about the same time. so cliff notes: 55 pilot jet Wont idle backfires/pops a ton occasional flame out the pipe very rough power when under 25% thorttle no carb adjustments seem to effect how it runs at all. Im 100% new the the WRs and appreciate any help i can get. we are running out of time before our trip and i dont have time to sit and read for hours like i normally do to solve a problem. Thank you!