quick idle question

[xanthras]

I have read the FAQs and some other threads. I just had one question that I must have missed. My 94, stock will hang a little over 3 k after it is fully warmed up (seems like it takes 10 mins or so). I figure it is lean and probably needs jets and whatnot. Here is the question. Why is it that when I let out the clutch a little the idle returns the the normal 1200?

FYI - in case it matters. I live in Upstate NY s the temps are 50's-80's.

I was figuring that I can adjust the idle while it is fully warmed, and I would be forced to use the choke longer or deal with it the way it is, or re jet.  Prolly not rejet till the fall if i do.

THANKS!

[joshr08]

have you pulled your plugs?  what color are they?

[xanthras]

Who do you think you are asking logical questions!.... I mean... that would be a no. I will have to do that. The shop that cleaned my carb this year said it was extremly lean and recommended the DJ kit. I passed on that due to what i have read on here. I will have to get back to you on the plugs.

[xanthras]

Since i am at work right now and cant get the plug info, lets say they are whitesh which is lean right? Why would the idle drop after I release a little clutch?

[joshr08]

when you release the clutch to lugging the motor down.  i can release my clutch to kill the motor if i like. 

http://gstwins.com/gsboard/index.php?topic=41199.0 you should check everything here.  anyone of these things could cause your problem.  a few people have dj kits and like them most stay away just for the price side if nothing else on the gs is a very simple carb and you can do the same if not better then a dj kit with different stock jet sizes.  If your taking your bike to the shop for carbs your prolly not checking your own valves and that could be an issue as well.  I have never been to a mc shop that have really even known how to put a tire on right let alone do a valve job on a bike that you actually have to change valve shims.  mileage on bike?

[xanthras]

Yea I read that. I will have to dig more into it in the fall. I just started riding this year so I would like to keep the bike running till the weather gets crappy before I do anything to the carbs myself. Got a baby on the way so I have to get in as much now as I can! oh yea, an its a 1994 3300mi. on the clock.

[janeuner]

A stock '94 with 3300 miles?  The problem has to be clogged pilot jets - it has been parked way too much =)

Its a slow day today, so lets see if I can explain what is going on in the carbs.  I'm going to refer to this diagram from bikebandit, just so you can see what parts I am referring to.

Up to about 30% of engine output, the pilot jet {19} provides all the engine's fuel.  A spring {7} keeps the main jet needle {32} all the way in, closing off the main jet {31}.  As air flow through the throttle valve {4} increases, air pressure between the diaphragm{10} and the diphragm cover {8} decreases.  The air pressure difference starts to overcome the force from the spring, lifting the diaphragm/needle and opening the main jet.  The further the needle opens, the more fuel gets delivered.

Herein lies the problem: As the idle speed drops from clogged pilot jets, people will tend to push idle screw in further, and slowly opening the throttle valves.  This increases air flow at a lower power level.  By itself, this would be fine - the engine will idle off the main jets.  However, a warm, fast running engine will keep the main jets from closing until something (like a throttle valve) restricts the air flow.  Thus, the main jets must stay closed when at idle.

All you should have to do is clean/replace those pilot jets.  It might be possible to soak them in carb cleaner for a few days, but I wouldn't count on it.  15 years of calcium buildup has probably left them close to useless.  Just order some new pilots (and while you are at it, a fuel filter for the probably-rusty fuel tank), swap them out over the weekend, and give it a go.  

Good luck~

[xanthras]

Ok so my idle issue, which I was willing to live with until it got colder here just took a turn for the worst.  The other day I start off normally, it's about 80 degrees out. After she warms up the idle changes from the normal 1200-3000 down to 900 and she is acting pretty strange. It is hesitating like she was starving for something. Took a few flicks of the wrist at each light just to get going. I started to suspect the tank vent, pulled over and popped it open. No change after that. Finally got home and moved the choke lever back and forth several times. Started it up. Started well, and ran fine around the block figuring it was just a stick choke. Next morning I started it up and it started doing the same thing. I had to go to work in the freakin car I get home, pull the plugs, they are black. I tested for a vacuum leak using the wd40 method and then checked the float height via the drain spout/hose method. It looked dead on. What the heck is going on here? Is the choke fully manual? Or just partially? I feel like either there is a piece of junk in the carb that is letting it flood or the choke is stuck on... Help? Please?

[xanthras]

I am doing more searching. One site was saying that there could some junk in the needle valve. Is there a good way to flush this out without tearing it all apart? Will draining the bowls even help?

[joshr08]

save yourself the trouble and take the carbs off and clean them....why are people so lazy to the point that they will do 100 different useless things in hopes of fixing the problem not even close to what they have been doing.  in the time you have F***ed around i could have done your carbs 10 times stop being so damn lazy or stop asking for help.

[ineedanap]

save yourself the trouble and take the carbs off and clean them....why are people so lazy to the point that they will do 100 different useless things in hopes of fixing the problem not even close to what they have been doing.  in the time you have F***ed around i could have done your carbs 10 times stop being so damn lazy or stop asking for help.

We should put that in the wiki...or at least make it a sticky.   

[xanthras]

i know i know. I was just thinking that since i had a shop do it in October and again in June that someone like me that has never done it would just screw it up or that it is something else. I will get it taken care of one way or the other. How is it that the carbs have this many issues...

Thanks anyways.

[joshr08]

  i would seriously look for a new shop or get a manual gs carbs are the easiest thing you could possibly work on as far as carbs go.

[Punkalflufen]

I was just thinking that since i had a shop do it in October and again in June that someone like me that has never done it would just screw it up

You will do a better job then them, get a shop manual if you don't have one already and there are guides and topics in the forums about re-jetting so you will have plenty of info all you have to do is take your time and label stuff like all the hoses when you take the bike apart so you know where it goes when you put everything back together.

[LimeyYankee]

I have read the FAQs and some other threads. I just had one question that I must have missed. My 94, stock will hang a little over 3 k after it is fully warmed up (seems like it takes 10 mins or so). I figure it is lean and probably needs jets and whatnot. Here is the question. Why is it that when I let out the clutch a little the idle returns the the normal 1200?

FYI - in case it matters. I live in Upstate NY s the temps are 50's-80's.

I was figuring that I can adjust the idle while it is fully warmed, and I would be forced to use the choke longer or deal with it the way it is, or re jet.  Prolly not rejet till the fall if i do.

THANKS!

Thanks for posting your problem, because my 07 with 6500 miles does the exact same thing.  It's completely stock too, and was running fine until recently.  As you stated, will run fine when cooler but halfway through my commute at temps in the mid 90's the idle will hang at 3000k.  If I just leave it alone, it will return to regular idle after about 10 sec, but I can also do what you say and let out my clutch a little while in first to make it go down back to idle quicker. 

I was going to run some carb cleaner through the tank and see if that helps, if not looks like I'll be pulling the carbs for a cleaning.

Matt

[xanthras]

Calling Joshr08! Alright man I took your gently put advice. I have my carbs off.  Not that bad to do actually. Been cleaning. There was some junk in there. Carb cleaner and compressed air ect. seemed to work. However. Here is where it gets interesteing, You know those plastic covers that sit over the diaphram? Well it looks like one of mine got cracked near the screw and someone put some epoxy over it, and then painted it black...It was noticibly not as tight as the other carb. Pretty sleazy. Tomorow I am heading over to the shop I was dealing with to complain. Would that cause some of the strange symptoms that I was having? I have not disassembled that part yet because I want them to see it. Anyways. We will see what they have to say....What was that one of you was saying about finding a better shop?

[The Buddha]

I have those tops - sell ya one for 15 shipped.

OK the crack near a screw - is that near the O ring ... and do you think the crack extends into that O ring area ?

If that is the case it will cause idle hover, and a bit of a raspy idle.

However if it was not near that O ring and it has a leak into the top of the diaphragm area, that will make it idle just fine, but will cause the bike to not run above a certain rpm for a specific load. Like 1st gear you'd make redline, 2nd, 9K, 3rd, 8k, 4th 7K, 5th 6k and 6th 5K - somethign like that.

Now if you managed to make a crack into both areas ... you prolly have both of these.
Cool.
Buddha.

[xanthras]

Yea it looks like i may need the cover at least. I will take them apart tomorrow to check the diaphram but first I am going to drop the carb on that crappy shops service desk tomorrow and see what I can get them do. I'm pretty pissed about it. I mean, fine they broke it. But they didnt say anything, epoxy it, and spray paint it black to cover it up.... WTF? I will get back to you tomorrow.

Thanks Buddha.

[jeremy_nash]

of course the shop will say that it was like that when they got it.   one shady enough to do that will also pass the blame.

I know its my opinion, but I'm sure alot of people will agree with me

[xanthras]

Shop mechanic admitted he epoxyed the cap. They are replacing it. Of course, they said they didn't think it was causing an issue. Tomorrow we will see how well of a job i did on the carbs.