Slow to return to idle

[jomama]

After letting off the gas , it takes as long as 20 seconds to settle down. I have had these carbs off and cleaned throughly many times and replaced the pilot jets and diaphrams and also made sure the slides are nice and clean and close freely when on the bench. I am starting to think there is another culprit here. Its not the throttle cable either . It sure seems that these machines can be quite quirky about the carbs. I do have the floats set at 22mm which i know is high . It does not flood but after trying to eliminate everything else it just dawned on me ths may be the problem. Any thoughts on this?

 

[reed]

its all trail and eror but you can check your float level with some clear tubeing attached to the bowl nipples and bend along the side of the carb toward the top if the fuel goes higher than the lip of the carb top your def to high. iam thinking its 1mm below the lip. the symptoms your telling about is usually an air leek in some of the normal places. spray some carb cleaner where gaskets are present (intake boots get cracked also) you also need to manometer synch your carbs after changes. thead search air leeks and manometer synch good place to start. good luck and paitance it can some times take a little while to sort carb probs out.

 

[jomama]

Trial and error indeed. I been trying and making a lot of errors. I have replaced the carb mounts a year or so back and have used propane and starting fluid to detect a leak w/o results . I have an old style set of mercury filler carb sticks and gone that route too. Tomorrow am i am going to yank them for the umteenth time and reset the floats say at 26mm and see what happens . Hell i have done this so many times i may go out at midnight and do it without any lights just cause i can.

 

[reed]

ya Iam hearing the words your keybording. frustrastion sets in dont kick the dog yet hahaha. still it sounds like an air leek somewhere. maybe you introduced some, added pods?

 

[jomama]

Once again i am mulling over the past trial and error steps and i just came into the house and another possibility hit me. I have the vacuum hose that runs to the fuel petcock disconnected and plugged thinking more vac for the engine. I have been running with the fuel lever in the prime position. After i have little lunch, i am going to reconect it and see if anything changes. Hey at this point i will try anything and this is a quick test. A report will follow.

 

[jomama]

I did reconnect the petcock to the vacuum port and found a slight air leak afterward which i sealed w/clamp. Only marginal inprovement . Heres another question, if the little O rings beneath the washers on the idle mix screws are bad, would placing a finger over the screw hole while running show a difference?. I dont know where these O rings are supposed to prevent air coming from. Mine are a little fllat and not in the best of shape. I would think the air would naturally be sucked down past the screw and it would show up when plugged w/finger but then again so far i have been wrong about everything else i have tried. I try to think logically here. If a vac leak is causing an engine to idle fast, then it should stay idling fast and not settle down at all. My symptoms are that of something not closing such as a butterfly but they appear to be .A vac leak is not going to seal itself and slowly bring the idle down .

 

[niko]

hello,

What version of pilot jet have you:

the MI-n 151067 without holes! (original pilot jet)

or
BS30/96 with holes on side

I 've a similar problem with a rebuilt kit with jet pilot with holes on side. Since I 've put the old (i think originals) jet pilot it's really better. Now I can say i've a idle, not really good but i've one!!

 

[jlearning1]

what year and version is your bike

 

[jomama]

Hey there J, so sorry for not responding earlier but between all the things summer has tp offer and the fact that I have all but given up on this thing have made me lose interest. However in answer ot your question, its a 80 G, special . I have tried everything and am still at square 1. I am almost leaning now to the TCI unit. Its new quirk along with all the former problems is it will siddenly increase RPMS from 1500 to 3000 all by its self and only when it feels like it , will it settle down to 1500 and then eventually die. I GIVE UP .I am seriously eyeing the cutting rorch with each new problem.New diaphrams, new poilot jets 1size up .45, pilot set screws at 3 turns, new plugs, floats set and reset many times, carbs throughly cleaned and recleaned and recleaned again at least 5 times, new carb mounts, synced and ballanced with merc sticks . Nothing has worked. I have not touched the elect timing as it has never been touched and only have seen these faults in an old style point ign systey with a faulty advance mechanism. This one is electronically controlled.
also there does not seem to be any way to check the tci unit to prove its within specs which arent listed in the haynes book anyway. I just love the old " REPLACE WITH A KNOWN GOOD UNIT". How many of us have that option? .

 

[OliverB]

If you have the Keihin carbs and have not yet replaced the o-rings, do so. My '80 behaved much the same way and was cured with o-ring replacement.

 

[jomama]

Just what "O RINGS" are you refering to? The ones beneath the pilot jet screws?. If so I have already done so albeit with some generic ones from an O ring assortment kit which i fitted to work. Maybe they arent exactly right. Anyway where are the exaxct ones available from?

 

[jomama]

As I rethink all of my attempts at solving the above problems, one thing finally hit me, the last time I set the float level I set t at 22mm which I know is extremely high. However it hadsnever flooded since but is it possible that having too much fuel in the bowls would cause a erratic and fast idle problem? Just a thought .

 

[jlearning1]

Hello Jomma

I noticed you said you went up 1size on your pilot jet screws. Search this forum for rejetting procedures. I not sure, but if you went up one size on the pilots, then you must resize something else. Search for rejetting.

Good Luck

 

[OliverB]

The recessed screw on top of each Keihin carb is called an air mixture screw. It is this screw to which I am referring. Can't say about the o-rings you chose to use.

 

[jomama]

Today i just reset the floats to 26mm and its still the same . It will hang up at 4 grand and until the throttle is bliped it wont move down and then only very slowly. It is for some reason spitting back through the right carb intermittingly. I still think its that GD TCI unit which of course is uncheckable and no one makes a new replacement. I hate to do it but i really think its going for parts or junk.

 

[xschris]

If its spitting out of the carb it could be a bad or out of adjustment intake valve. The 4000rpm hang up might be a part of that and if you have no air filters on it its leaning out.

 

[jomama]

Chris i see you are here in upstate NY, I am just outside Warensburg and if I decide to let this thing go, you will be the first to know. Anywho, I just went through the valves last week so they are right. This is maddening. I have a website somwhere that sells elect ign units for every type of atv there is and I am going there to see if anything is available . But first I may try to substitute some older honda carbs I have hidden someplace even though I doubt thats the problem .

 

[xschris]

You are about 2 1/2 hours from me I live by watkins glenn. Even if the valves are set right they still may not seat right. Pull the carbs off and look inside the intake you should be able to see the intake valve. Spray some wd-40 or something wet in and around intake. Turn the engine over and look to see if any bubbles comes from the valve. Then you know if it is not seating.

 

[jomama]

Last night i took the carbs off again and seperated them and replaced the seals on the inner side of the card throttle shafts which i knew from a test were sucking air. No change . If anything worse. I have done it all. New diaphrams, pilot jets, set the floats in every position possible, throttle shaft (inner and outer ) seals, rubber plugs, synced and adjusted , advanced and retarded spark, new plugs, checked coils ,checked air filters,reset valves and nothing has changes its gotta be in the CDI that makes it want to stick between 3 & 4 grand . I am going to push it down in the shed and either parts it out or cut it up. Its gonna be a flip of the coin that decides it. From now on i am sticking with a bike that has only 1 carb and is easy to gets parts for ( any year ) like an old sportster.