another jetting question

[jamienlogan]

I have a 1999 400ex with a 440 11:1 compression piston and t4 aftermarket pipe. I put a 170 main jet in and I was wondering what is the other jet is for? I also have my air fuel screw turned 3 1/2 turns out. It also pops on decelaration.

[underpowered]

the other jest is your pilot jet. It controls up to 1/4 throtle, it is sometimes called the slow jet or idle jet. go up a little on your pilot to decrease the popping and cracking. maybe mess with your air fuel a little more to help as well.

[jamienlogan]

what # is stock pilot? I was told to run a 45, and where can I get some?

stock is 38, I would recommend a 40 or 42 depending on the temperature