I have been spending a lot of time trying to jet this thing. Before anyone brings it up no air leaks,1990 with just about a complete new motor, dr. Q head .050 squish checked, 87mm bore, Poul turner pipe, and stock filter no air box lid. Set up for 110 octane and running 32 to 1. Everything else stock. I finally think I got it but it is kinda different then what anyone else is running. I'm at 3500' and its been 95 to 105 degrees the last 3 weeks. 20 pilot, 1 1/2 air screw, needle all the way down 1st position, and 400 main. Had to drop pilot because it wouldn't idle without idle screw all the way in and air screw had no effect besides shutting down bellow 2 turns out. Now it idles and I have the idle srew 2 turns out. Idles perfect. Kept droping needle from 4th position and every time the mid range cleared up. When I hit the last position it was perfect. Started with a 380 main and after plug reading I went to 400. 390 was a little to close but probably ok. After all this and thinking back, when I dropped the needle the last time I think it help the idle as well. So now I'm thinking I have a worn needle jet. My jet needle is fine, no signs of wear. Hard to tell if needle jet has wear. Don't have a way to measure.

I have been spending a lot of time trying to jet this thing. Before anyone brings it up no air leaks,1990 with just about a complete new motor, dr. Q head .050 squish checked, 87mm bore, Poul turner pipe, and stock filter no air box lid. Set up for 110 octane and running 32 to 1. Everything else stock. I finally think I got it but it is kinda different then what anyone else is running. I'm at 3500' and its been 95 to 105 degrees the last 3 weeks. 20 pilot, 1 1/2 air screw, needle all the way down 1st position, and 400 main. Had to drop pilot because it wouldn't idle without idle screw all the way in and air screw had no effect besides shutting down bellow 2 turns out. Now it idles and I have the idle srew 2 turns out. Idles perfect. Kept droping needle from 4th position and every time the mid range cleared up. When I hit the last position it was perfect. Started with a 380 main and after plug reading I went to 400. 390 was a little to close but probably ok. After all this and thinking back, when I dropped the needle the last time I think it help the idle as well. So now I'm thinking I have a worn needle jet. My jet needle is fine, no signs of wear. Hard to tell if needle jet has wear. Don't have a way to measure.

Dropping the needle should not affect the idle.  What needle are you using? 

It sounds like you may not be addressing the right circuits for the problems you are having.

Needles and needle jet ware out.   .0002" to .0003" ware inside the needle jet or on the outside of the needle will make a noticeable change in the way the engine runs.  .0002" to .0003"resolution is beyond the ability of the under $300.00 digital calipers.   We have bore gages, ring gages setting fixtures, and air flow bore gages that can easily measure the inside the needle jet. 

A worn needle jet will cause a rich condition at 0 to about 3/8 throttle opening.   Moving the clip in the needle DOES NOT AFFECT the mixture until the throttle is open to about 3/8 to 1/2 opening.  If moving the clip seems to affect the idle mixture, you have some fuel circuits way off and they are severly overlapping causing you to address the wrong circuits. 

For your temperatures and 3500' elevation lI would recommend that you start with the following jetting and fine tune from these setting.

Start with a new needle and needle jet.

R-0 389 needle jet
6DK3 jet needle with the clip in the 2nd position from the top
air correction jet removed
4.0 slide
22.5 pilot jet
air screw at 1 1/2 turns
3.5 float valve
400 main jet.

The Paul Turner pipes and silencer often requires a smaller main jet because the pipes are "over-restricted".  This will usually make the main jet size very sensitive to temperature and altitude changes and is very easy to burn a piston on engines that have any porting.   

Scratch that, found it

Motorgeek did you mean Poul turner pipe require larger main jets? You said smaller and I'm sure that was a mistake. Any way I did a little handy work on my pipe. Welded a new stinger on there. The problem is the rear cone of the pipe where it meets the stinger is smaller than the stinger diameter. So I hacked it back and re welded the stinger on. Golden

Well I got it dialed now. Deffently had a wore out needle jet. Replaced needle jet with a R0 and the pilot was to lean. So I bumped it back to the 22.5. Put the needle clip back to the 2nd position. Motor geek hit the nail on the head. Had to put the air screw 2 turns out.