Stock J carbs on an 1135 will not idle

I just got my '81 J engine together, it is now an 1135 with 10.5 to 1, GPZ1100 cams and a Kerker. With the original J carbs with KZ1100 mains (fat side) and #40 idle jets It fires up on the choke but will only idle if you turn up the idle speed screw alot, then the idle hangs up when riding. Sounds lean right?. I drilled the pilots from .016 to .020, same result, then switched carbs to the old set that I know worked (when it was a 1000) and opened up the pilots to .0225, same thing, I really had to open the idle speed screw to make it idle again, and it hangs up also.. Ignition advancer is ok.......I put the manifolds on with hi-temp RTV and let dry during assembly. I sprayed starter fluid around carbs, no leaks...I am baffled!

Cv carbs are the devil.... What did you change intake wise? Pods? Stacks or factory airbox

pods and a kerker were on it when it was a 1000. All I did to the carbs was bigger pilot jets, kz1100 needles and main jets. All day spent drilling those idle jets out .002 each time, same crap

Are you sure your not getting to much fuel at idle.
Big CC and small cams should have a strong pull thru the carbs.
I suggest going back to the stock 37.5s.

I agree with this guy but somethings not right , i think you have two problems. Check all vac ports are blocked off for airbox, then start with recommended jets and you know main jets dont effect idle so as long as you have the basic understanding your good there, next hook up vac guages youd use to sync and see what ya got. If you didnt change anything you should idle and go lean upper in rpms after big bore.

It started as a KZ1000LTD engine with the super wimpy cams. I had 37.5 pilots and 122.5 mains in it then with the pods and the kerker and it ran fine. That was a 9.5 to 1 engine with pencil tip cams. Now 135cc bigger with much bigger cams. Stock KZ1100 pilots are #40 with a wide spread of mains. Mains are of no issue here since our concern is the idle circuit. Just to get it to idle with no throttle application, it takes about 2 full turns of the main idle speed screw from it's previous working position, then once revved up, the idle hangs up big time. It really has me baffled.What kills me is this is a just fired top end. Someone said check the cam timing, which I did twice during assembly and all seemed AOK.

How long did the cars set while the engine work was being done ? If they sat with fuel in them the pilot jets or tiny holes that go to the idle mixture screws may be plugged. Unless youre very famliar with those Cvs theres passages you dont know about, air passages too

The second set of carbs sat 1.2 years with old fuel residue in them, but no crud. Pilot jets are wide open, as far as other passages, where?. The second set of carbs tested were the originals from the engine before re-build, the first set of carbs were rebuilt by yours truly...but not "boiled out". Pilot and main jets are open for sure.

That's why I believe there's an issue with vac leak and or sync issues, what carbs are you running? Are they bs34s or vim series mechanical slides

they are the stock CV 34s that came on all 81+ KZ1000/1100s. Since I just did the top end and it has been sitting, I just drained the gas, put fresh fuel in and ran it around, same bad idle. I turned the idle speed down so it won't hang up between shifts and it will decelerate properly, I just have to hold the idle. So after this, I came back, off came the carbs, then the coils, oil cooler lines and valve cover. Then I checked the cam timing and it is good, then checked valve clearance hot, got .002+. So I just ordered new intake manifolds for a start.

But you did the spray test and got no acceleration which means no leak there, and there's no open ports or leaks elsewhere creating a lean condition, since there's no more hanging at high revs it's just the idle issue, don't give up your almost there. I know you said pilots are clear but maybe there is lacquered gas in the passage way behind the actual jet orifice ?

it is not hanging up because I turned the idle speed screw down to where it felt normal when you chop the throttle. I will take the carbs to work this week and confirm the pilot/mixture ports are open.