I've got an '09 z250 that is currently running very lean. I went to adjust the needle and saw that there is no adjustment on it. Is there a replacement needle that is adjustable, and if so, do you know the part number?

 

If all you want to do is raise it, put washers under it. There are 100s of needles to pick from. My favorite is the 5L1. Its a pretty rich needle with a sharp point.

 

Good idea, I'll give that a try.

Do you mind taking a look at this diagram and telling me what items 54 and 57 are?

http://www.partzilla.com/images/diag...1/107/0010.png

 

57 is an air jet. I don't see 54 pointing to anything. It could be the DIAPHRAGM ASSY... whatever that is.

Alpha Sports - Suzuki ATV Parts Catalog

 

#57 is the pilot jet.
#54 is the assembly as stated above. It's called a assembly but it physically looks like a gasket. It acts like a pump.

 

28 is the pilot jet

 

I stand corrected. And thank you.
I looked up #55 and seen pilot jet and didn't pay no attention ti the "air" behind it.
My bad. LOL

 

I kinda doubt it has anything to do with the pilot at all. Airjets usually meter air for the needle jet and changing that airjet would affect upper rpms. Yeah, it may (or may not) supply air for the pilot circuit too, but it doesn't meter that air. Its really tough to tell from that diagram as the airjet would screw into the part of the carb that isn't shown.

 

I found a copy of the manual, and it refers to them as

pilot air jet
enrichment diaphragm

 

Look at http://www.mikuni.com/pdf/vmmanual.pdf

Pilot air jet is misleading