Dont know thing about jetting...

[JBacon]

I've loooked at the FAQ thread but I still dont understand a fricken thing about jetting. Im jetting because I might get a HMF pipe and im running a UNI filter right now. Should I just take my 250ex to a honda dealer or someone I know to let them rejet it if I get the HMF?

[ALEXANDERJASON]

BUY A DYNOJET KIT. ONCE YOU GET THE KIT, AND READ THE INSTRUCTIONS AND LOOK AT THE PARTS, THE JETTING THREAD WILL MAKE MORE SENSE.

YOU SHOULD BE ABLE TO TACKLE IT YOURSELF.

DON'T GIVE ANY MORE MONEY TO THE "STEALER", ESPECIALLY FOR SOMETHING SO EASY AND WITH LOTS OF HELP ON THIS FORUM.

[ryanh250ex]

First off, thanks for looking at the FAQ, at least you looked before you asked

You need to be a little more descriptive about what you dont understand.

Without knowing specifics, I'll take a stab at helping you.

An engine is like a air pump. the pump (engine) works based off of three basic ingredients- air, fuel, and spark. For basic purposes, spark usually doesn't need to be adjusted regardless of mods (it could benefit a litttle bit but thats getting pretty technical). that said, that leaves us with two ingredients, air and fuel.

For the engine to run properly, a certain amount of air needs to mix with the given amount of fuel flowing into the motor. this mixture is called your Air to Fuel ratio- commonly abbreviated as A/F or AFR. for best gas mileage, the ideal AFR is 14.7:1 , but if you're trying to make maximum power, you want roughly 12:1.

So let's say you're running lean (not enough fuel to mix with the air) , that would mean you have a high (example: 17:1) AFR. not good for the motor, you'll experiencing overheating, backfiring, poor performance.

A rich mixture will lead to bogging, poor performance, etc. This will lead to a low AFR (e.g 10:1 or so). It means too much fuel being mixed with the air.

So the whole point of rejetting, is to provide enough fuel to appropriately mix with the air coming in. stuff like airbox mods, exhausts, aftermarket air filters, all that stuff will increase the airflow coming into the engine. so you need to add more fuel. Rejetting does this.

edit: It is totally a DIY job, have no fear!

[JBacon]

Alright ryan, I understand why you need to rejet now, but I dont understand where the Pilot,fuel mixture screw, and etc. is. I wouldnt know what to take off and switch out and stuff. I dont want to do something wrong to my carb and hurt my engine.