Hi everyone. I'm currently in the process of building a klx330 with fcr35 carburetor (old model) while the bike is running great with good torque, the carburetor seem to have a problem of leaking gas (I suspect the case of overflow but cant find the exact reason why). I'm used the rebuild kit to replace the orings and the gasket but the problem still remains. The gas is leaking through the slow jets and the needle (area showed in the picture)



But the funny thing is, when testing without the bowl, the carb is working fine and dont even leak a drop!!
When instal the bowl and adjust the float bowl level to the lowest possible, it still leaking.

If anyone ever occured the same problem. Please let me know, this drives me crazy.
Thank you guys so much!

 

Another note: I also replace the float valve and the float valve seat as well.

 

You need to figure out why the float valve opens when you put the bowl on.

 

I still dont know why, the float valve dont have any problem sliding in and out of the valve seat. Will go over the bowl today to find the problem.

 

After so many tear down of the carb. I found the reason why. The slanted fcr has two air passage along the "KEIHIN" logo on the side. If these two passage clogged up the carb will draw fuel from the bowl no matter what the possition of the float valves ( suction I supposed). Lesson learned: "remember to check all the passage when cleaning a carburetor".