Carbs: Before I dig in

I have read the guides, i have searched the interwebs... but I would like some guidance / thoughts.

81 XS-650, BS34's stock main 132.5, stock pilot 42.5, but Needle Jet - 336 YO, and Jet Needle - 5IX11. also stock air jet of 135 and 2 1/2 turns out mix screw. float bowl height 21mm +-. AND i fully cleaned these carbs so NO hole is clogged.

Notch is in middle.
Pipes = Double D's from Pandemonium (yes i know i lose some perf on top end)
Air Filters = Uni Foam Pods

now symptoms w/ setup is bikes turns on 1st kick no chock and idles perfect. min i throttle it dies. needle position is not an issue, that doesnt kick in till 4k rpms. if i cover the air jet, OR put chock and rev it works but not 100%. hence the below setup ill try?

Searching around i have seen some peeps do 45 pilot, 140 main, 3rd notch, 2.5 turns out, and 125 air jet. This will be my 1st attempt tonight. will that work?

I have a TON of jets i got from mikesxs so if you'd like send me some suggestions.

a pic of the pipes lol

Try 3 turns out with the mixture screw, then 3 1/2 if that improves the situation swap to the larger pilot and 1 3/4 -2 out on the mixture screw.
What is your idle speed?

Tried 3 turns out even 4. no improvement. What i do see on current setup is soot ? (spelling) on the pilot holes , or might be the mixture holes near the intake?

I would think soot in the carb would be a timing problem but let's see what others think.
If no improvement with the mixture screw, yes change the jet.

thanks!

Needle position has a very strong effect on off-idle mixture; the main circuit is never completely "turned off" even when the slides are fully down. Even at closed throttle, engine vacuum pulls fuel up through the atomizer. If you don't take account of that kind of secondary effect in tuning you'll get nowhere.

Before you try tuning carbs, everything else needs to be right--ignition, compression, valve condition and adjustment, the whole enchilida.

Correct,
Valves checked, timing is good, timing chain tension is good as well. compression on each cyl is around 111-115 psi. great spark (though i will get new plugs) trust me i have def banged my head against the engine for awhile. i have worked on ALL my friends stock xs' and they all work. why? bc they all have long pipes or exhaust and etc. my bike is a bit on the ehhh side where i def have to modify the carbs a bit.

Yes you do, especially since they're the BS34s. They were so lean from the factory that any changes to the intake and/or exhaust mess them up. More on the needles - while sustained slide lift doesn't occur until rather late on these CV carbs, like around 4K, the slides do jump open momentarily when you whack the throttle open, like when coming off idle. That momentary "bounce" could be what's killing the motor. But, is it because it's too lean or too rich? Well, it could be either, that's what you'll need to track down.

I'd start with bumping the mains up to a 137.5 or 140 because it's easy. If it helps, fine, if not, you can leave them there because that's close to what you'll probably need in the end anyway. Next, I would play with needle settings. The stock fixed 5HX12 needle measures about 50mm from the clip down to the tip. Your Canadian 5IX11 measures 50mm from the top clip slot. That means setting it in the middle #3 slot will have it 2 steps richer than the original. That may be too much. If no joy here then it's on to the idle circuit. I would start with just the pilot jet increase to the #45. Many times you needn't fool with the air jet, the pilot jet change is enough. And I should mention that this air jet is for the pilot circuit only, it doesn't feed or effect the other circuits. There is another separate, fixed air jet that feeds the midrange/main circuit. Changing the air jet is a way to fine tune the idle circuit. One size change doesn't have as big of an effect as one size change on the pilot jet itself. Because of this, it allows you to achieve richness levels in between pilot jet sizes. But, doing a 4 size change to a #125 like you mentioned could be pretty near the same as doing another pilot jet change. I wouldn't go that much, maybe only 1 or 2 sizes.

So, it could be lean mains causing the stall, or too rich of a needle setting, or too lean of a pilot circuit. It's best to do carb changes one at a time. Do a bunch at once and you won't know which did what.

So abit if success today, i installed a140/45 setup and127.5 air jet. It idles really good, and revs slowlly very well atabout 3/4 turn then bogs a lil bit. It was late and i was tired so i called it a night. BUT before i did lol i took it for a spin. From 1st gear i can only give it about 1/4 throttle and i have to goto 2nd so it doesnt die. If i try cranking it, it dies. Im going to try and go back to stock air jet, and 2nd clip fr the top? Now why would gas cone out frone the back of the intake?

Sounds like you have a fuel level problem in the bowls. Either the floats are set wrong or the float needles and seats aren't working right. You won't be able to properly tune the carbs until you take care of that problem.

In your carbs the float chamber vents through 2 holes in the intake bell. Since you used brass from Mike's XS instead of the real thing from Mikuni, you may have bad float valves. It's also possible that your fuel level needs to be lowered (floats raised) a little bit.

Edit: 5twins, it hasn't happened yet, but one of these days you're going to hit hit "Send" and find my post there!

First come first served guys!!
The floats maybe twisted too. The level will be set to the lower side is sitting if that makes sense. In a nutshell, check both sides of the floats, and give a twist to make them even

Not sure what you guys mean by twisted? For the brass floats, whats the height? I am pretty sure (short term memory loss?) i have the black plastic ones

The float itself could be twisted

Ah gotcha, ok ill report back in a bit. So lets say they arent twisted, what should brass FB height be? Im pretty sure i have the plastic aftermarket ones from mikes. i replaced all the parts and seals, choke etc on that carb.

The BS34 brass float spec is 27.3 ± .5mm. The plastic floats are 22 ± 1mm. Measure both sides of each float because, as Angus mentioned, they can be twisted or tweaked on the mounts, one side sitting higher or lower than the other.

Success so far, next test is drive down the block.

So sitting still i have a SMOOTH full throttle.

Changes made if anyone wants
Floats btw are not twisted and height is perfect. could have been when i covered the intake w/ my hand?

150 Main, 45 Pilot, 127.5 Air jet, and 2nd clip from bottom. plugs look great, but true test of that is running it down the block a bit.
starts on 1st kick NO choke.

Being able to cold start with no choke could indicate you're a bit rich. Normally, these bikes always need the choke for a cold start, even in warm weather. Plugs may be good looking now but today's gas can take some time to color plugs. Check them again in 50 to 100 miles, they may not look so pretty.

will do, they looked pretty good. also i just went down a couple of blocks before almost running out of gas and she ran like a champ!

Ok guys, rode a good amount past few times. 50 miles? plugs look perfect. just where they should be. so if ANYONE does the same setup of exhaust i would recommend the settings on this thread