jetting question about FMF Powercore

My bike is 06 WR450F, just changed to FMF Powercore with the stock headpipe. And then did some jetting. But the bike become slow respond in 0-1/2 throttle. And more difficult to pull up my front wheel. Can anybody advise me how to improve it? :thumbsup:

Old setting is:

Stock exhaust and removed all inserts.

Pilot Jet: 45

Main Jet: 168

Jet Needle: stock Pos 3

Fuel screw: 1.5 out

Now setting is:

FMF Powercore

Pilot Jet: 48

Main Jet: 170

Jet Needle: stock Pos 3

Fuel screw: 1.5 out

I put the FMF Powercore on my 07 WR450 and at the same time did the following:

removed air box snorkle(sp)

removed grey wire

removed AIS system

installed JD Jetting

168 main

48 pilot

red needle 4th from the top groove

zip-ty fuel screw out 2 turns

The bike runs great.:thumbsup:

My bike is 06 WR450F, just changed to FMF Powercore with the stock headpipe. And then did some jetting. But the bike become slow respond in 0-1/2 throttle. And more difficult to pull up my front wheel. Can anybody advise me how to improve it? :thumbsup:

Old setting is:

Stock exhaust and removed all inserts.

Pilot Jet: 45

Main Jet: 168

Jet Needle: stock Pos 3

Fuel screw: 1.5 out

Now setting is:

FMF Powercore

Pilot Jet: 48

Main Jet: 170

Jet Needle: stock Pos 3

Fuel screw: 1.5 out

Move your needle up 1 groove, notch 4 and go from there. The needle is definetely your problem.

kenshaw720, I had done all free mods, but I don't have the JD jet kit, so I am not sure how to reference your setting, thanks.

Move your needle up 1 groove, notch 4 and go from there. The needle is definetely your problem.

I found that the bike will be choking in high RPM if i put the needle higher. And the engine will be easier stall in fast open throttle. How to prevent this?

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