Hi Jay. First of all, the DJ kit doesn't supply new side air screws. I thought I should mention the screws could be wrong as a possibility. I've seen carbs butchered and pieced together. If you can show a pic' of the screws or give detailed info of their appearance, that would help. They're most likely correct, but you never know. If the screws are correct, and you say the passage is clean, then the only other way the screw could have no effect would be if the carb slides are out of synch and the idle's been adjusted beyond an rpm the screws can reach. Your bike should idle well at 1,100 rpm's. The air screws should effect idle at this rpm.
As for your exhaust, the stage 3 DJ kit was designed with a free flow exhaust in mind. I believe your exhaust will be more restrictive than the kit was designed for, but it will still work. It just adds to the jetting trial and error. I'm familiar with the K&N ovals.
As for the DJ base settings (with a free flow pipe), they say to use the 138 main, the jet needle e-clip in position 2 (from the top), make pilot screw adjustments to assist the stock pilot jet, and remove the two floatbowl vent lines.
I assume the bike is ready for re-jetting. That means the carbs are cleaned inside... any o-rings inside are good...the floats have been set close to .94" (be sure the floats are even on each side and not tweaked)...the two plastic jet needle spacers are installed in the correct order... the manifold o-rings are good and the manifolds have been replaced (you mentioned some manifold issue)... the carbs have been manually synched (fully closed and fully opened slide positions) in preparation for a vacuum tool synch...the two floatbowl vent lines removed and the nipples left open...the side air screws adjusted for highest rpm and the pilot fuel screws (underneath) adjusted at a good starting point (depends where they were when the bike was stock and running well)...usually an ADDITIONAL 1/2 turn out is a good starting point for the pilot fuel screws...the valve clearances should be set correctly...the ignition timing set correctly... the plugs replaced...the ovals oiled correctly.
If you make any needle adjustments, you must re-synch the VM carbs everytime. To accurately re-jet these carbs, you must synch them with a vacuum tool. Get the levels so the difference is no more than a 1/2" from the highest to the lowest level.
I haven't jetted for your exhaust, but I'll make my jetting suggestions.
Definitely the 138 main,
Try the needle e-clip in the 4th position with a JETTING SPACER on top the e-clip... be sure the thicker plastic spacer (ring) goes on top of the jetting spacer and the thinner plastic spacer goes under the e-clip, (to possibly save work and if the bike is ready for re-jetting as I described, you may want to do a needle circuit plug test before making my suggested setting and then make a needle adjustment that makes sense, if needed),
Adjust the pilot fuel screws out as I said earlier,
Be sure to remove the floatbowl vent lines to avoid fuel starvation.
The pilot fuel screws are sensitive to adjustments. Be sure you only seat these sharp tipped screws lightly. It's common to have them set at different points (ex: 1 1/4, 1 1/2, 1 5/8, 1 1/4) after final tuning because of differences in each cylinder. They should end up within a 1/2 turn of each other though. I assume you know how to adjust the side air screws for highest rpm's?
Pilot circuit re-jetting can take some time to get exact. Once you're close, small adjustments can still effect performance and plug color. I plug test at a steady 35 mph in 4th gear. There's still some minimal needle overlap at these speeds but it works good enough for me. I go a few miles and chop the bike off and read. I always do this after any higher speed plug tests.
I test the needle circuit at 1/3 throttle position in 5th gear. I mark the throttle. I test for a couple of miles and chop the bike off.
For the main circuit, I go full throttle.
I can get away with these high speed tests where I live. Be careful if you do the same.
I seem to go against the "norm" by getting the needle circuit right, then the main. I get the needle circuit running good and the plug color good, then I install the largest main I have that doesn't create any bogging or flat spots during a 5th gear roll on at 60 mph. Works for me. I always choose a bike that will perform as it should in every day riding situations, even if I do give up a couple mph at the top end.
Let me know if you have any questions.
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