Needle Clip, Pilot and Main

[Shee_Man]

Alright from what I understand...

Pilot = idle to 1/4 throttle

Needle clip = 1/4 - 3/4 throttle

Main = 3/4 - WOT

 

What about are different RPM levels... at the moment my shee is boggin until powerband then takes off like a bat out of hell...

Would this only be my main?

Are the Pilot, needle clip and main only control the air/fuel for different throttle positions regardless of how high or low you're revin'.

[fixitrod]

[fixitrod]

I know this doesn't help the rpm question completly, but this will show how the different jets do help each other out. I do see what you are saying. That's why being good at jetting is an art.

[Toomey Banshee]

BennBB has a jetting faq floating around in here. Read it, learn it, live it. He's the man when it comes to jetting.

[BenBB]

Here's another real similar illustration. To answer your question, yes it's the throttle position because the carb doesn't know what RPM the motor is spinning, all it does is meter how much fuel goes in, depending on how far you open the throttle (i.e. how much air goes in, the carb tries to maintain the right air/fuel ratio). So it's possible to be real rich on one circuit and lean on another and have a similar scenario that you described, or be just a hair rich/lean on one circuit and perfect everywhere else...

 

OK for example if your needle was way too rich and all other circuits were perfect, it would start and idle fine, and once it was WOT it would run fine, but if you held it at 1/2 throttle it would run rough, or when you stabbed it to WOT it would stumble; because that middle throttle position is feeding too much fuel, once it gets past that rich condition and on the mains it can rev out clean. All else being the same it wouldn't matter what RPM the motor was spinning, but higher revs would probably help through the rich transition...

 

Anyway, jetting is alot of trial and error, so play with one circuit at a time and you'll get there eventually. Good luck.