Engine Bogs From 0 To 1/8 Throttle

[BansheeBruce]

I just had a dune port job done. After reassembly the engine bogs right off idle (from 0 to 1/8 throttle). I turned the air screws in to 1/2 turn out and it got a little better, still a slight bog off idle. I also turned up the idle slightly. These are stock carbs. Other mods: No air box, T5's, +4 timing adv, V-Force, 350 main, Toomey needles 4th groove from top, stock 25 pilot jet. 1000 ft elev. Does this mean its lean off idle? Should I go up to the next larger pilot jet? Thanks in advance for the help. This is a great forum.

[DUNEDEMON]

Yes, it sounds like you're lean on the bottom, depending on the port work done you may be lean on top too. I like to get WOT dialed in first, do a top gear run, kill the engine, do a plug color check / plug chop to see where you are at, then work back from there. Try dropping the clips on the needles one position, and adjust your pilots and air srews accordingly to clean up the bottom end if you feel good about the 1/2 - 3/4 - wide open throttle position jetting. This is just my advise on how I work out jetting issues.

[Ducman]

Yup, go up one size on the pilots if you get to within 1/2 turn out on the airscrews and turning them in makes it run beter. I like to do the pilots first since they add fuel to all of the jetting circuts affecting WOT conditions along with the mains, that is, as soon as you crack the throttle the pilots add 100% of the fuel that will flow through them and they dont shut off, they keep flowing through WOT. So if you get the mains dialed and then add larger pilots you will be a little richer on top then you were before you added the pilots. You mains may need to be rejeted as well. Do a plug chop. In my opinion that is the only reliable way to check main jetting, reading plugs can be decieving and if you throw in a new set and do a quick run through the gears at WOT to the top of 6th the plug electrode insutator will still be white except the 2mm brown band at the base of the electrode insulator. You need to remove a portion of the threads on the plug to create a notch to easily see the 2mm band. 2mm = just right, More than 2mm = rich, less and 2mm or no band = lean.

[Banchetta]

Try a larger pilot and go from there. Jetting is trial and error, find what YOUR shee likes....let us know how you make out...sounds like your almost there....