Hello I was wondering what the stock round jet for the 250ex was. I am planning on getting a compleat HMF system and it says I have to use 125 Keihin round jet, so I wanted to know what the stock one was. Thank you.

 

They mean the main jet and you should also get a needle with your kit...Then you will need to turn the adjuster screw what HMF prefers for their exhuast oy tune it by how the engine sounds.

Here is a schematic of the carb of an 03 250ex as I wasn't sure what year you have.

http://216.37.204.203/Honda_OEM/Hond...=13&A=157&B=21