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Please help , this is my first post. Carb issues?

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So i have a 2004 crf450r and recently i purchased a mega bomb header and the power core 4 FmF slip on exhaust. As of right now i have a 48 for the pilot and 155 for the main , and for the needle set i am using is the one provided in the FmF re jet kit, which is on slot 5. Pretty much the bike appears to be running lean it is backfiring and popping on de acceleration .  i would appreciate it a lot if anyone could give me their opinion on what they think? Here are a few pictures of the bike if anyone cares to see it:). Also if it helps to no i just recently replaced the jug gasket and head gasket, also put new shims in and had to set timing cause it was all taken apart, i did this right before i put the new exhaust on . i live in Arizona it is currently 91 degrees and about 1100 feet above see level currently.

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1. Wrong jets: 45/170/NCVS needle (stock R needle) on 3rd or 4th clip. DO NOT USE  the FMF needle or any of there jets ,as they are not flow tested.

2. Deceleration popping is a pilot circuit issue

3. Since you pilot is right now way too big, your lean ness is probably coming from a sitcky hot start plunger, or an air leak at the oring on the fuel screw, or carb boots, etc

4. fuel screw should be at appox 1.5 with a 45 pilot

4. tighten your header mount

5. repack your silencer

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