Lean or Rich Pilot?

[Saul76]

Still fighting my pilot jet. Feels like the rest of my jetting is just where I want it - but I feel a 'sputter/stutter/ "just" off idle.

I got this video and you can hear the 'stutter' after each - lol - jump .. just as I go out of camera view and come back in - this is all in 1st gear to keep speed low and to reproduce this 'stutter' as much as possible.

Listen and tell me what you think.

http://www.youtube.com/watch?v=UVRxIE4XQeU

NOTE - the actual 'riding' or lack thereof isn't relevant to the thread and certainly not what the thread is about. Yes - it's really lame 'hops' over a lil dirt mound - I am WELL aware - lol. Again, the video is just shown to diagnose if the pilot sounds lean or rich.

Thanks guys!

[Honda 250r 001]

lean...

[Jason Hall]

Is the slide Installed with the cutaway towards the rear of the carb??? Have you tried lowering the needle??? Is the float set to high??? Sounds to me like It's rich on the needle. Lean on the needle would go boooowaaaa (flat spot or major hesitation) If lowering the needle Is no help, then try dropping the pilot 1 size, and make SURE you have the Choke/Idle adjustment correct. Do you have the Choke/Idle adjuster turned way out??? If so, turn the Idle adjuster In (TURN IT TO THE RIGHT LOOKING AT IT FROM THE TOP), then back the air screw out slowly until you get a nice even Idle.

[Saul76]

[i]Originally posted by Jason Hall Is the slide Installed with the cutaway towards the rear of the carb???

slide is installed correctly, yes.


Have you tried lowering the needle???

No, not yet. Will raise the clip a notch tomorrow.


Is the float set to high???

Set to factory specs.


Sounds to me like It's rich on the needle. Lean on the needle would go boooowaaaa (flat spot or major hesitation) If lowering the needle Is no help, then try dropping the pilot 1 size, and make SURE you have the Choke/Idle adjustment correct.

I'll mess with clip position.



Do you have the Choke/Idle adjuster turned way out??? If so, turn the Idle adjuster In (TURN IT TO THE RIGHT LOOKING AT IT FROM THE TOP), then back the air screw out slowly until you get a nice even Idle.

Right now idle adjustment/choke knob is turned almost fully out (meaning you can't pull up on choke much at all)

Thanks for the advice - I'll give it a go tomorrow.

I'll actually start with idle adjustment & A/F screw before I move the clip.

[dynofox]

Its sounds lean to me as the rpms seem to hang especially at the end of the video.

[Jason Hall]

The girgle you hear just off Idle Is RICH!!! If the choke/Idle adjuster Is all the way up the Idle will do CRAZY things. You need to get the Idle adjuster down farther. How far out Is the air screw??? Try setting the air screw to 1-1/2 turns out, then turn the Idle adjuster down as far as you can and still Idle. If that doesn't work, then you'll need a different size pilot. But until you get the Idle circuit set close you won't know If you need to go bigger or smaller. Just remember this, your running It right now with the choke almost all the way on!!!! I like a 45 pilot with a PJ carb.

[Honda 250r 001]

Originally posted by Jason Hall
The girgle you hear just off Idle Is RICH!!! If the choke/Idle adjuster Is all the way up the Idle will do CRAZY things. You need to get the Idle adjuster down farther. How far out Is the air screw??? Try setting the air screw to 1-1/2 turns out, then turn the Idle adjuster down as far as you can and still Idle. If that doesn't work, then you'll need a different size pilot. But until you get the Idle circuit set close you won't know If you need to go bigger or smaller. Just remember this, your running It right now with the choke almost all the way on!!!! I like a 45 pilot with a PJ carb.

but notice how it doesnt idle steady, that is a sign of leanness.

that girgle you speak of may be a misadjusted slide. :/

[Saul76]

I've tried now to turn the idle/choke all the way down - fully closed. neil suggested the same. The back off air/fuel screw until I get an idle.

I tried that with my 48 & a 62 sized pilot and it won't idle with the choke lever fully turned in - no matter how much I back off the air/fuel screw.

I've got a 62 pilot in there now I wanna try out tomorrow as the 62 let me get the idle adjust knob closed the furthest.

I also lowered the needle by raising the clip one position to see how it affects the mid range.

I most certainly need to get myself a bunch of pilot jets - right now I only have a 42, 45, 48 & then jumps right to 62.

[Jason Hall]

What Is a misadjusted slide???? Please explain!!! On a PJ carb you Can't adjust the slide. It sounds to me like he has the Idle circuit running on the choke. The PJ choke Is a type of needle jet that mixes gas with air that BYPASSES the slide.

[Jason Hall]

Saul have you pulled the choke plunger out of the carb??? I ask this because not all the plungers have the same bore. A 38mm PJ uses a bigger diameter plunger than a 34mm PJ. Maybe someone has the wrong plunger In the carb. Thats just a thought, the plunger should fit snug.

Does this bike have an adjustable timing plate???

[Saul76]

Originally posted by Jason Hall It sounds to me like he has the Idle circuit running on the choke. The PJ choke Is a type of needle jet that mixes gas with air that BYPASSES the slide.

Jason - this is what led me to believe the pilot in there was too small maybe? Cause I had the A/F screw turned out just about 2 turns (shop manual calls for 1 7/8) but needed to turn idle WAY up to get a steady idle with A/F screw @ 2 turns out (stock 48 pilot)

[Saul76]

Originally posted by Jason Hall
Saul have you pulled the choke plunger out of the carb??? I ask this because not all the plungers have the same bore. A 38mm PJ uses a bigger diameter plunger than a 34mm PJ. Maybe someone has the wrong plunger In the carb. Thats just a thought, the plunger should fit snug.

Plunger seems fine - I guess. Snug fit.


Does this bike have an adjustable timing plate???

No.

********************
I think putting in a 62 is a mistake - I'm gunna pull that out tomorrow before I ride and put the 48 back in and try to get an idle from the 48 with the choke knob closed as much as possible and see if the change in needle clip position alone helps.

The 62 seems absurd high of a pilot to run. Probably be fouling plugs too easily.

btw - thanks for the replies Jason.