Jetting Advice

[DirtDiggler69]

I'm running a graydon 2-1 with 33 PWK non air striker , just rebuilt the top end . Current jetting is a 50 pilot , 190 main and eek needle in the 4th clip down . Seems really rich and stumbles when you give it throttle . Air screw is out 3 turns , will idle . So it seems that maybe my pilot is too rich , and my main as well .

My other issue is I have a couple small coolant leaks around the head , I'm thinking of changing the head gasket out and using permatex copper spray on the new gasket . I'm gonna use a borescope down each spark plug hole before I pull the head to see if there is any coolant in the cylinders , it's not smoking like it's burning coolant , just looks like rich exhaust . Any jetting advice on the 2-1 is appreciated .

[DirtDiggler69]

So I dropped to a 185 main and a 50 pilot , things seem much better and idles like a champ w/o blipping the throttle . I have a whitish exhaust , not billowy but noticeable and as it idled and warmed up it seems to get better too . The engine still doesn't seem to rev smooth , but it's better . Maybe I'll try the 180 main and pick up a 170 and a 175 .

The leak around the head is minute , but still there . I am concerned coolant may be getting into the combustion chamber , will that cause erratic or stumbling acceleration?

 

 

I originally was wrong , I had a 195 main and a 55 pilot to start with .

Edited July 1, 2012 by DirtDiggler69

[dcalsv02]

Try your air screw at 1.5-2 turns out. Get an eek needle in it and try leaning your main down a little. Pilot is pretty close. Maybe a 45-48. Get a new head gasket.

[DirtDiggler69]

New head gasket and spray copper sealer on the way , I have a EEK in it . It's in the 4th notch down I'll get a 45 and 48 pilot and see what that does . Main is now at 185 , so I'll get a 180 and 175

 

Now what happens when you move the needle jet?

 

I am picturing that if you move it up ( towards the carb cap ) it richens up the idle circuit

 

And down ( furthur into the pilot jet ) it leans it out ( more of the needle protruding into the pilot thereby displacing air/fuel .

 

Is this right or wrong?

[dcalsv02]

I just double checked my pilot when i was changing my main and my pilot is a 52, so your 50 maybe spot on. Mine may be a little rich.

 

in your carb you have a jet needle (which is the needle with the clip) and a needle jet (where the needle goes into). My Eek needle is on the 2nd clip from the bottom. And yes, if you lower the clip it richens it. The jet needle helps tune the 1/4-1/2 circuit.