I just bought a 2002 520EXC and rode it for the first time last weekend. It seemed a little slugish down low and after reading through this forum I ordered a JD jet kit and Zipty fuel mixture screw.
The first thing to install was the Zipty but the original screw would not come out as described in the instructions. I removed the float bowl and there is a collar on the screw that prevents it from coming out of the bowl. Is this normal? I also noted that the Zipty would not go through the opening in the bowl, no problem I just installed the screw and then slipped the bowl over it.
Now to the JD kit. Per instruction I installed the blue needle at the 4th clip position and the 172 main. I brought the mixture screw out 1 3/4 turns and the buttoned everything back together.
Went to start but no-go. I took the bowl off and there is no fuel. I went back to the original mixture screw and got a couple of attempted fires but still wouldn't run.
I feel like I have caused the float to close and not allow fuel into the bowl but can not see where. Has anybody else had this situation or can you offer suggestions.