Pilot jet quickly

[s3v3red]

Quick question, if my bike doesn't stall until the fuel screw is all the way in do I need to downsize my pilot jet? Most people say "if it idles fine when screwed all the way in, replace it". Saying this is different than what I'm experiencing. It stalls out, but only when the screw is completely in.

[Beau 88]

If you turn the air screw closed or in until it seats and the bike still runs the pilot jet is too large so go down a jet size or two. If you have to adjust more than 3 turns out to get optimum power and a good plug reading the pilot jets too small and needs a larger size.  ?

[s3v3red]

So, is that a no? I'm running the carb at 1/4 turn out. It dies all the way in.

[FORMA MOTO]

You adjust a pilot (fuel screw) by idle speed.

 

Normally, but not always, turning the screw all the way in with a proplerly jetting pilot circuit, will cause it to die.

But that is not really all that important.

 

It's all about idle speed.

 

Starting with one turn out on the fuel screw on a hot motor:

 

Start motor, and drop idle with idle screw as low as it will go

Raise the idle with the FUEL SCREW to as high as it will go.

If it's too high, lower with the idle screw, and check to see if the fuel screw can be adjusted to raise the idle any more.

Keep doing this until the desired idle has be reached using the fuel screw.

Shut off motor and accurately determine the exact amount of turns out you now have and write it down.

 

At this point, less than 1 turn out means you are rich on the pilot jet, more than two means your are lean on the jet.

[Beau 88]

Koolaid explained it better especially on a thumper i didn't ask and assumed it was a smoker sorry if i confused you 

[s3v3red]

My screw doesn't seem to affect idle... I'm trying to diagnose this thing but it's getting to be a pain. Spring, washer an o-ring all look good. Needle too...

[FORMA MOTO]

Idle is affected only by:

 

Pilot jet

Fuel screw

Slide height / idle screw

Slide plate seal condition

.... and AIR LEAKS!

 

If you have not ever serviced your hot start or choke plungers, it's time.

The hot start nut also leaks sometime because they are plastic. Replace with Zipty nut.

Sounds like it 's time to really service the carb.

 

http://www.dirtrider.com/features/protips/141_0707_keihin_fcr_carb_rebuild/

Edited April 24, 2014 by TheKoolAidMadeMeSick