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Problems with 3/4 to full throttle response

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Hey fellas, hope someone can help! I wanna ride this weekend. I know burned will have the answer.

Here's my info:

1)04 YZ450F

2)4500-8500 ft (track at 4500), 85-100 deg, dry utah heat

3)no modifications except o-ring mod and raven acc pump cover (don't know if either has done any good)

4)main 162, pilot 42, needle 4th position, fuel screw at 2 turns

5)throttle response seems good up to half throttle. then hitting 3/4 and full throttle bike revs with no response or blippy response (hard to explain). Also, bike won't stay started with clutch in. It starts real easy in gear or neutral, but dies when I stop and idle. not sure if both issues are same problem.

6)the running issue doesn't appear to change whether or not the bike is cold or hot, but typically I don't run my bike that hard till its warmed up.

Also, i just checked the valves, they are good. The head pipe is bent a bit but doesn't appear to restrict flow. There is no popping at all. I am going to check the pilot circuit when i get home.

Thanks for the help.

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Well, my fuel screw is at about 1/2 turn right now and seems to run best. Idle screw was not set properly, causing my bike to die when sitting. So should I try a 45 pilot or move the needle setting?

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what fuel screw?

it doesnt need a bigger pilot jet.smaller if anything but if you have an aluminum fuel screw thats causing the idle issue.

main jet needs to be more like a 155.

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I made a mistake on my original post. My pilot was a 45. I changed to a 42 and throttle seems smooth at 1.5 turns on fuel screw. I still have the 160 main and 4th needle position but now my bike power has significantly reduced. I believe its a half to full throttle issue. I noticed when I rode the track yesterday and corners that I normally take in second i had to take in third. Should I still try going to a 155 main or should I try moving the needle position first?

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