Agreed. That just sounds huge, but if it's working best do it.

Can you get much change in idle rpm with adjustments to the fuel screw, particularly from 1 to 3 turns out? Can you find the best/highest idle between 1 & 3 turns with rpm dropping with turns in & out from highest idle rpm?

I started with the #38 after 351 kit, and went back down to the #35. My airbox and exhaust are pretty open, and at around 3,000 ft. A few members here run a #40, but not too many of them, and I don't recall any running larger than #40.

 

I have a 331, and had to go back to a 35 from a 40...but, I also went from 2500 ft to 5000+ ft.

This is a question I've always wondered about. Is the Pilot circuit always operating? By that, I mean, is it always open and the hole uncovered to the throat of the carb? If so, the Venturi action is always pulling some fuel out of that hole, so a 40 Pilot and an X Main would always be a bit richer across the entire throttle opening range than a 35 Pilot and an X Main.

I know I could figure it out if I pulled the carb and examined it...but, asking is so much easier to do!

Nevermind! I found the answer, it was as I suspected. "The primary purpose of the pilot system is to supply the mixture at idle. It continues to supply fuel throughout the entire throttle range, but after about 1/8 throttle is reached the MAIN SYSTEM starts to put out an increasing percentage of the total mixture up to full throttle." That comes from "Care and Feeding of the Keihin carb". So, yep, a larger Pilot yields a higher fuel delivery throughout the throttle range, even though it is a lower and lower percentage of the total fuel delivery as the throttle is opened wider and wider.

 

And honestly, it's almost nonexistent after about 1/4 throttle.

 

pilots are just supposed to feed fuel at idle, just enough to keep it running. it is shooting a miniscule amount of fuel compared to the main jet, just enough to keep it running at idle and decel.

i am at virtually 0 feet above sea level. texas is so damn flat! im originally from virginia so this was really weird at first to me. anyways, went with the 45 for troubleshooting purposes, and the fact with the 40 my bike seemed really lean. i rather have it a little rich at first because it seemed like it was starving when it cut off and was refired. I have not ridden it yet today, just got off work and about to head up to my buddys shop. if any body is near my sea level, what are you running?

 

I think of it as perhaps a logrithmically decreasing percentage of the final A/F ratio: although the Pilot has some effect at higher throttle openings, it's increasingly overshadowed by the effect of the Main jet to the point it may only be detectable by an exhaust sniffer.

 

well i got to ride the bike tonight. runs way better now, didnt shut off on me either. idle felt pretty good. it idled for 5 to8 minutes, revved it up, took it outside, putted ubout 2 miles? laid into it, revved it all the way out. basically simulated the conditions from the last few days, and it didnt stall. Why a 45 is seeming to work, beets me. maybe its the houston air lol. going to put some miles on it this weekend in austin, well keep the thread updated. NOT saying the solution is looking like a 45, more like the solution is and always has been proper jetting...where its not the same everywhere!


Oh, third gear clutch ups are stupid fun. still not a ktm killer, by far, but damn it was worth the money. i cant wait to track it!

 

UPDATE ON ERRATIC IDLE AS OF 11/1/12

Mine is no longer being weird. at all. whatsoever. running a 40 pilot now. But, it actually started idling right, on its own, with the 45. the trick?

Ride the damn thing. I think it just wanted to give itself its own break in. I have no other real explanation as of right now. it literally just idled correctly. I havent had it shut off in 500 miles.

To those interested in the kit: I RECOMMEND IT HIGHLY. Bill is a great person to do business with, always helpful and reliable. The kit itself, does absolute wonders for this bike. What a difference!

 

Glad to hear you got it sorted out. Big bore on these bikes make a world of difference !!