XJ700x idle adjustment issues - mechanic stumped

Hello All,
I was gifted a neglected xj700x last July and i have been slowly working on getting it back on the road. At this point, I’ve already cleaned and rebuilt the carbs with the support of xj4ever, changed the air filter and all the fluids, and i also synced the carbs. The issue i am having is that even with the carbs synced, the idle adjustment screw does not seem to want to make fine tune adjustments.

even at 4 turns out i have to leave the choke about half way engaged throughout the entire warm up process. Once hot, the bike will roughly idle but if i try to increase the idle speed even a little, once i blip the throttle the idle surges to 3k+ RPMs and hangs there. Its like i cant get the idle to stabilize anywhere in between 1100 and 2900 RPMs, only outside that range. This issue hinders me from ever being able to properly color tune the bike, and i cant get it to run at only 2 turns out.

as i type this i realize that the obvious answer is to take them to the church of clean, but i need to know if there are any other issue that could be causing this. I have the bike at a mechanic shop right now and they are stumped as well. They checked for air leaks but couldn’t find any and they also took a look at the carbs and said they look good from a visual standpoint point.
Could clogged carb channels really be causing this idle adjustment issue? When i cleaned the carbs i only dipped them as i didnt have access to an ultrasonic cleaner. I did however spray carb cleaner through the main air jet while covering the mixture hole and fuel shot right through the outlet on all carbs.

any questions or advice would be greatly appreciated.


XJ700 Maxim X

 

I had a similar issue with mine when I was getting it up and running. You didn't go into much detail about how you cleaned them, but if you did not clean every single hole, it just will not run right. When I did it, It took a lot of time to go through and find every hole in the idle, run, and enrichment (choke) circuit and clean them, including buying a tig wire cleaning brust kit. The idle jet is especially small..... Take some time looking in the float bowl area spraying with carb cleaner and seeing where it comes out in the carb tunnel, then see what other holes are in the carb tunnel and back spray them, mine were clogged solid and it took cycles of carb spraying and baths for them to clear up.
It sounds like you are running lean, which is usually a case of the carbs, though it can be other things. Only once you are certain the carbs are perfectly clean would you want to start going down other avenues. If you are sure, many people will point you to the o-rings in the carbs, specifically the throttle shaft ones, as when they go bad they let in unmetered air and bingo, you are running lean with a crappy idle, only running with choke on, and surging/hanging idle.

 

it appears there may be some mix up or confusion over the terminology of some of the screws /jets , in op's question.
the idle adjustment screw is underneath the carbs in the centre,
you state " 4 turns out" , are you refering to the mixture screws ,which are on the top of the carbs?

 

And did you remove these and squirt cleaner through the idle circuit to see it coming out here and the progression holes.
It looks like you have a lot to learn about the intricacies of these instruments, there are a myriad of things that could fail them, the answer is not directly in this forum, it's with you - each and every passage and orifice clean as new, then each float valve height dry then wet set, then each carb bench synched carefully.
In all the steps of stripping and reassembly one mistake, one false step can cause an issue..

 

https://xjbikes.com/forums/threads/in-the-church-of-clean.14692/
Take the time to read through this thread. There is a number of issues that could be making the carbs act up. You did the bench sync, and you have the bike running, that is a good start. I am guessing the carbs need to have a little more TLC time and make sure the choke ckt jet in the bottom of the bowl is clean. Also, make sure the diaphragms are good with no pinholes. Making sure they are set into their seating grove, so no air is leaking by.

Do you currently have all the air box rubber back in place to the carbs? Being able to test each diaphragm with compressed air blown into the opening just under the Top Hat covers facing the air box is a good way to check proper working condition.

 

Hey everyone, thanks for the replies!

To start, the carbs were definitely zestfully cleaned trust me on that haha. I removed them enough times to check. Also, I rebuilt them with a complete kit from Chacal so i have no doubts on the o-rings or other components. When i mentioned 4 turns out, i was referring to the pilot mixture screw, sorry that i didnt specify.

with all this being said, i took the PO’s word (my father in law) that the valves were checked and in spec and so i never checked them. Guess what the problem was? Apparently all the valves were badly out of timing, luckily not enough to do any lasting damage. The shop readjusted the valves and it was a night and day difference in performance and reliability.

I still have one problem though: when the bike gets warmed up (and i mean bumper to bumper warmed up) the idle get choppy and inconsistent and i find myself having to blip the throttle to keep the bike running when at a stop. it seems that i may be running rich but the temp gauge is also closing in on the red when symptoms occur.
from what i read, running rich shouldn't cause overheating but can any one confirm if this is normal when driving in traffic? (This is my starter bike so not much experience!)

the high temp is the only thing that makes me second guess my “rich mixture” diagnosis. I plan to color tune to know for sure but would love everyone’s feedback.

edit: forgot to mention that i am currently 2 3/4 turns out, though i experienced the same problem at 2.5 turns out (pilot mixture screw)
XJ700 Maxim X

 

high temp would be caused by a LEAN mixture not a RICH one

 

Thanks! Makes sense, i often over complicate things in my head. Ill make some small adjustments and will check back to share the results