Fine tuning Carbs and Idle after installing a new/used set.

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My original set of carbs were gummed up after sitting for several years,so found a clean set on Ebay.Inspected diaphragms,cleaned float chambers(they were clean) replaced float bowl gaskets,checked set floats,didn't touch jets,new insulator bands,removed PAIR system.Synced carbs,as close I could get them,but can't get them to hold a consistent idle.Ranges from 900-1500.
On the road bike runs smoothly except below 2k.Rideable but trying to get smoother.The idle will hold,bike will start with full choke and run on it's own when warm.I'll check for obvious vacuum leaks and such.Any other suggestions other than pulling the set.Looking to do anything external before resorting to digging into the jets.
 
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+1... keep using seafoam until it clears up, or pull the carbs and clean the low speed jets.
 
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mznyc
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Ya I should have said I'm gonna run a tank of high test with Sea Foam through it before I start poking around.The inconsistent idle points to air leak/vacuum to me, the carb expert.Not!
 
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When I picked up my current 1100, the carbs were not performing well... the bike sat for a while and the jets were dirty. I ran several tanks of seafoam and other cleaners such as Berryman's through it. Even went on a "slow speed" ride for almost a hundred miles. It was getting better, but not quickly. I finally dismantled the carbs, cleaned the jets, reassembled and still ran several tanks of seafoam before it cleared up 100%.
 

ST1100Y

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The inconsistent idle points to air leak/vacuum to me, the carb expert.Not!
A bouncing idle would lead to that theory...
You mentioned having removed the PAIR system... positive that you've blocked every now unused vacuum line there?

As for checking on jets: place them over a strong flash-light for getting a visual on the bores; one might poke through them with the bristle of a nylon broom or such, won't cause and damage but might help getting any crud out...
 
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Ya I should have said I'm gonna run a tank of high test with Sea Foam through it before I start poking around.The inconsistent idle points to air leak/vacuum to me, the carb expert.Not!
Actually, a slight fluxuation of idle at operating temp. is FIRST indication of carbs out of sync;), IF carbs are performing good otherwise. Doesn't look like neceassily the case with this scenario, with them possibly having other issues.
 
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mznyc
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A bouncing idle would lead to that theory...
You mentioned having removed the PAIR system... positive that you've blocked every now unused vacuum line there?

As for checking on jets: place them over a strong flash-light for getting a visual on the bores; one might poke through them with the bristle of a nylon broom or such, won't cause and damage but might help getting any crud out...
I'm pretty sure I got every one.Now if something came loose I can't attest to.Blocked all holes where PAIR pipes attached to heads,capped the large nipple on the front of the carbs,removed the T between,carbs 2 & 4 and capped them.The sync hoses never seemed "tight" on the nipples on the cylinders,snug but felt like it should have been harder to slide them on.I'll check those first and all caps .
Actually, a slight fluxuation of idle at operating temp. is FIRST indication of carbs out of sync;), IF carbs are performing good otherwise. Doesn't look like neceassily the case with this scenario, with them possibly having other issues.
Bike runs great above idle all the way up to redline.
I'll re-read the sync procedure as it was my first time and take another stab at it.

Original hoses.Anyone have a part # or size of those hoses for NAPA or Autozone.Last time my local store didn't have them.
 

John OoSTerhuis

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I'll re-read the sync procedure as it was my first time and take another stab at it.

Original hoses.Anyone have a part # or size of those hoses for NAPA or Autozone.Last time my local store didn't have them.
N.B. The Clymer manual's carb sync instructions are wrong, in case you're using that manual. Carbs 1, 2, and 3 sync individually to the base carb (4), period!

For bulk metric hoses, try a foreign car parts store. Take the old hose with you.

John
 
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mznyc
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Ya I had your post from a previous thread John and synced to #4.Thanks for the heads up.
 
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mznyc
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IMG_3978.jpgHere's a shot of sync,think that's close enough for a good running bike?
 

John OoSTerhuis

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So all four stay in sync on the meters while the rpm oscillates between 900 and 1,500...?

Curious.

Edit: partially blocked fuel filter..?
 
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mznyc
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New fuel filter.Idle will hold a setting,once it settles and the revs come down.I twist the throttle a few times and it may settle to a higher/lower idle.take it for a ride pull up to a light and it settles to a different setting,no rhyme or reason as engine is up to temp at this point.throttle cables were lubed and adjusted,choke is clear at fully off position.ill the-check those,and hoses,also patched a rusted section where header meets xover so I'll check that but felt I had that tight.
 
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New fuel filter.Idle will hold a setting,once it settles and the revs come down.I twist the throttle a few times and it may settle to a higher/lower idle.take it for a ride pull up to a light and it settles to a different setting,no rhyme or reason as engine is up to temp at this point.throttle cables were lubed and adjusted,choke is clear at fully off position.ill the-check those,and hoses,also patched a rusted section where header meets xover so I'll check that but felt I had that tight.
Fairly sure you still have a restricted pilot circuit. Unfortunately, you may have to pull that carb bank, remove bowls, pliot jets, mains, slides and emulsion tubes to get things cleaned up. Just a FYI, anything that would get trapped in pilot jets STAYS there because of direction of flow, and atomiizing hole in end is to small for anything foreign to exit;). I honestly can say I've never had these Kiehn's apart, but am a guru when it comes to the 4bank Mikunis on my 34yr.old Venturer1100 Yammy. All very similar in nature, and will cause similar if not the same running issues.....just sayin', from decades of experience with bike carbs:).
 
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mznyc
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Can you verify that the throttle bellcrank is returning all the way to the stop when these symptoms occur?
I will John.I also will check throttle and choke cables,hoses,blocking plates from PAIR removal,and exhaust leaks,let cha know what I find.
 

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...throttle cables were lubed and adjusted...
hmm... the "lubed" just caught my eye... such can actually be counter-productive as the inside of the sleeves is nylon/Teflon coated, lube/oils might dissolve the plastics due which the cables then stick even more...
When adjusting the throttle cables always see that the idle does not change while moving the steering from fully left to right, and that the throttle-grip/bellcrank is snapping back freely in any/all steering positions...
 
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mznyc
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I visually checked hoses and couldn't find anything,put in a bottle of SeaFoam,and will re-sync carbs.After I run through the tank of gas I'll see how she's doing and report back.
This the the video of the first start up after un-run for more than half a decade and before I synced carbs and changed plugs.
[video=youtube_share;XwZP1sunRUw]http://youtu.be/XwZP1sunRUw[/video]
 
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