Questionable float level....

[Red_Rooster]

OK, Ive checked the Float level per Dave's and this forums instructions. It is exactly paralell, and 16 mm from the edge. The Needle Valve has NO groove in it, and the springy tip moves freely, but has spring in it. There is no noticeable play in the float body assembly, and the floats do not have any fuel in them.

HOWEVER, in an effort to figure out why it hardly idles, Even with the Idle screw ALL the way in, I turned the fuel petcock off, to see if it would increase idle as the float bowl emptied (leaned out..). Well, almost immediately (5 seconds or less) the Rpms increased, and it idled at a Higher RPM, More or less where I thought it should with the Idle screw all the way in. And whaddya know, the Air Screw now effects Idle as well.

As soon as I turn the petcock back on (2 seconds) the idle drops, and it barely runs. I turn the valve off, and it idles up again. This time I leave the valve off, and after 5 minutes or so, the expected lean drop occurs, and it dies (out of fuel).

Petcock back on, bike immediately fires, Idles high, and then back to low. Petcock off, and it increases again. All of this with the Idle screw all the way in, and the Air screw 1 turn out from seated. If I turn the Petcock 1/2 way on, the bike continues to run.

What could be the issue? My only thought is maybe the springy end of the needle valve has gotten too soft, so that the weight of the fuel opens the needle valve a bit, even with the floats adjusted, and it floods out....? Any thoughts?

 

[Red_Rooster]

Well, Lots of people have looked at this thread, but no replies. Maybe I didnt make sense, or maybe everyone was just as confused as I was...

I FIXED IT!!

Went out Last Saturday with Supply of Jets, and plugs, carb cleaner and a bunch of printouts from this, and other sites.

WOT test, spot on jetting = 155
1/2 throttle, spot on jetting with 1174 needle in mid position.
Heres where it gets funky..
Pulled the carb apart again, decided to try and raise the floats (less fuel in bowl). I changed it from 16mm to about 12mm. Reassembled and WaaLaa...Perfect Idle. Air screw is still 3 turns out with a 45 slow jet.

Will a 42 get me in the ballpark, or should I go down to a 40? its not that big a deal, as my local KTM shop has jets in stock for about 5 bucks, but want to be sure to get the right one. So which one should I get, 42, or 40?

Went on a 50 mile Single Track Ride yesterday...man, what fun. This is EXACTLY the kind of bike I was looking for as an addition to my big ol' XR650..

Thanks to this site, I got her runnin right.

 

[FruDaddy]

Sounds like you have the gas on when you think it's off.

 

[Red_Rooster]

Straight Down is ON, Horizontal is off, and straight up is reserve right?

 

[Rhodester]

I'd get the 42 and see if you end up between 1 and 2 turns out and the air screw. If more than 2 out, get a 40 and shoot for the same (1 to 2 out)....OR....get the 40 first and work it the opposite way....to get to 1 to 2 turns out on the air screw. At 3 turns out I'd suspect that the 40 would be the way to start.

 

[G. Gearloose]

And leaving the AS in the highest-idle position typically dials in an off-idle hesitation. Close it carefully to set best off-idle torque under load.

 

[canyncarvr]

Rhodester..G-Loose:

'...decided to try and raise the floats (less fuel in bowl). I changed it from 16mm to about 12mm.'

You guys just let that float by? :ohmy: (har har har)

Did I miss something? ..probably.

Something's upside down! It might be the carb! ;)

Raising the floats INcreases the fuel in the bowl. Changing them (the floats) from a 16mm to a 12mm drop is indeed raising the floats.

Turning off the fuel with any reasonable float level will result in the idle speed increasing as the bike continues to run. As the fuel level in the bowl drops, the air/fuel mixture leans out, the idle speed will increase.


At 16mm the kdx will probably pee on itself on the kickstand. At 12mm? You couldn't go 'round a corner without it peeing!

**edit**
BTW, considering the raising=less argument...you are aware that the float level is set when the tang just touches the spring pin on the needle, right? That was the point of the 'upside down' comment. If there is no spring pin, you would turn a carb upside down, let the floats rest on the needle and measure the drop. Moving the floats 'up' in that case effectively lowers the fuel level...'cuz the carby's upside down.

:nod: Yup!

 

[saveaux]

At 16mm the kdx will probably pee on itself on the kickstand. At 12mm? You couldn't go 'round a corner without it peeing!

...sigh...My Hero! :worship:

 

[Rhodester]

CC, you're right....I missed that.

 

[Red_Rooster]

Rhodester..G-Loose:

Moving the floats 'up' in that case effectively lowers the fuel level...'cuz the carby's upside down.

:nod: Yup!

yes...That is what I did. the measurement was 12mm, but now that you mention it, I measured in a different spot, so please disregard my "12m" comment as I must have been talking out of my butt... :bang:

I DID do my initial measuring with the tang just touching. So I "raised" the floats by a bit with the carb upside down, effectively lowering the floats. All I know is that now it runs pretty good with only slight off idle hesitation. Another 50 miles of singletrack today, and nary a hiccup. Thoug I am still running the 45 pilot with the AS 3 turns out. Ill get that taken care of soon....thanks for the clarification