22mm mikuni problems

[durandbagwell86]

My setup below. I'm having problems with my 22mm mikuni carb. It only wants to run with the enricher open ("choke" on). It starts on the second pull with the choke on and idles great, when I turn it off it dies, even when warm. I can idle it up with the idle screw for the slide and make it idle with the choke off, but when the choke is on with the idle screw in the same spot it idles crazy high. I have a 12.5 and 130 jets with the clip in the center notch. I don't know what's going on with it. Any help will be much appreciated.

-non hemi predator 212
-billet rod and flywheel.
-nrracing ported 18cc Honda head milled .050
-SS valves and 26lb springs
-cm push rods
-champion rocker arms
-.016 copper head gasket
-lash caps
-black mamba sr. cam
-head and side cover studs
-22mm mikuni with long intake and k&n style filter
-Robertson torque tube 3 stage header

 

[bdomit01]

Low speed jet is to small 12.5 is too lean for most applications IMO. Working better with the enricher on indicates that your lean. Put the 15 that came with it back in and see if it helps. You might need to step up to a 17.5. I've even used 20 and 22.5 before.

 

[Havasu Dave]

I can idle it up with the idle screw for the slide and make it idle with the choke off, but when the choke is on with the idle screw in the same spot it idles crazy high.

They will idle crazy high when warm with the enrichener on.

It sounds like you're trying to tune the carb with no throttle hooked up. A 12.5 pilot jet sounds lean especially at sea level. You didn't mention any adjustments with the pilot air screw.

Get the throttle working (if it's not) and try a 15 or even a 17 pilot jet. If you still need enrichener, you have an air leak, or too much air coming in via the air screw.

When I had to go through this learning process, the website below was very helpful to me. It might look tedious to read, but there are some good pointers in it for tuning.

Mikuni carburetor operation and tuning

 

[durandbagwell86]

I swapped in a 15 pilot jet and it runs and idles perfect. Had some gas leaking on the back side of the carb. I think I pinched the oring for the carb bowl, it didn't want to line up right. I think I'm going to stick the oring in the groove and stick it with some rtv.