I just put an hmf pipe on my 06 trx250ex. It came with a 125 main jet which I installed but now the idle is hanging and it seems to be fine tuned. Can someone tell me how to adjust the fuel mixture? Please explan where the fuel mixture screw is. Thanks!

 

look on the bottom of the carb towards the intake boot. turning the screw out richens the mixture.

 

Thanks, QuickSilver. I spent several hours adjusting it 1/4 turns at a time with and without the airbox lid. I can't seem to get rid of the popping on decel.... I guess I'm lean or have an air leak somewhere. I'll keep trying. Anyone have experience with this application? All tips, suggestions are welcomed.

 

Popping on Decel. might indicate the valves need adjusting.

 

none

 

Is that a 125 main from a jet kit like Dyno. Just remember there size is not the same a your original keihln jet. I tested a lot and found a 112 main and 42 pilot just about right, go to your parts counter and just get a 112 main, Dont tighten them down to tight or you"ll have more problems.

 

Thanks Guys! The main jet is a 125 Keihin jet that came from HMF along with the pipe. I doubt it's the valves as it didn't have a problem until I put the new pipe on. If it's popping, wouldn't that indicate lean conditions and that I would need a larger main? I plan on buying 2 smaller and 2 larger but wanted some feedback from you guys.

 

I had the same problem after installing a White Bros slip on. I was able to fix it by adjusting the idle screw. The one on the right side of the carb if your sitting on the quad. I had to turn it out quite a bit.

How did you adjust the fuel mixture screw? The one on the engine side of the carb. I can't figure out what tool is needed to adjust this. It kind of idles roughly and I need to richen it up.

 

Originally posted by: otsxo[/i]
I had the same problem after installing a White Bros slip on. I was able to fix it by adjusting the idle screw. The one on the right side of the carb if your sitting on the quad. I had to turn it out quite a bit.

How did you adjust the fuel mixture screw? The one on the engine side of the carb. I can't figure out what tool is needed to adjust this. It kind of idles roughly and I need to richen it up.[/quote]


The screw is called a D screw and the head is shaped like a D. I removed the D screw with some very fine needle nosed pliers and took a dremel to grind a straight edge in the head so that I could use a regular screwdriver on it. Honda wanted $128 for the tool....

 

huh. nobody caught that. fixed a lean condition by idling up? donno about that... Try using the guy-who-actually-knows-what-the-heck-he's-doing solution run a 112 and a 42. My bro's seems to work ok with a 115 and a completely backed out idle mixture screw.