keihn jets in mikuni carbs

[atvfreestylekid]

I have 320 main jets for keihin carbs in my stock mikuni carbs. these 320's and my old 280's are the same but the hole is bigger, as expected, on the 320. is a 320 keihin jet the same as a 320 mikuni? or do the holes the fuel flow through size different? thanks

[BigRed350x]

They are different. Not sure which way it goes, but one company uses the number to designate how much fuel flows through the orifice and the other company uses the number to designate the hole size. At least that's what I think it is... lol But yeah, they are different. a 320 for one is not the same as a 320 for the other.

 

If you have a 320 for a keihin carb, you have a freaking massive jet. That's just HUGE in keihin land. You might just have a tall mikuni jet. A 180 is getting pretty big in a keihin carb, so a 320 would be unheard of. I'm pretty sure if that's the correct number on the jet, you just have a tall mikuni jet.

 

- Jared

[atvfreestylekid]

Thanks jared. It must be a mikuni then. it's a little bigger than the 280's but not a lot The quad runs good once in the powerband. It has shitty bottom end though. It runs like it's rich down low but it's got stock pilots in it. and the main jet has nothing to do with the bottom end power does it?

[4stroker]

it must be a mikuni jet coz im pretty sure keihin jets stop at around 230 (at least for pwks anyway) if u need bigger keihin jets (for methanol etc) you have to get them reamed.

 

oh yeah and keihin sizes are in millimeters, eg a 230 keihin is 2.3mm diameter hole in the jet. mikuni numbers represent flow through the jet.

 

and if it is a tall mikuni when it is supposed to be a short mikuni jet, i think it will affect your jetting, as the tall jet will be protruding deeper into the fuel bowl. itll be like havin your float level set too high.

 

mark.