400ex bogs and hesitates to quick rev help

[dmaheryfz450]

hello guys i new to the forum i have a 400ex my problem is its bogging when you just cruise and then pin the throttle it will bog or hesitates to take a quick rev it has a fmf pipe keihin fcr37 carb 175main and 50pilot fuel screw 2 turns out and choke removed any help appreciated thanks guys oh and taking off the air box lid make no difference from what i can tell please help but it goes perfect once you dont pin the throttle heres a pic of it please help is so annoying it driving me :mad:

[2001400exrida]

is that all it has is the fmf pipe?

[rubbersdown]

Sounds like the typical off idle bog associated with the fcr carb. Its caused by the AP circuit. You can either try to time the AP squirt which can be a pain or I would suggest you just do the AP mod which USUALLY fixes the problem.
I know this is a tutorial for a bike with the 40mm fcr but they look and function the same so just follow these directions...http://www.squadpage.com/pandora/Professor%20RedBeard450%20How-To%20AP%20Mod.pdf

[dmaheryfz450]

yea it has stage 2 cam and crf450 timing chain and k,n air filter also