Hanging idle after repairs

[Larry D]

Set the screws to 2.5 turns out. Take all the tools you need to adjust said screws with you. Go for a ride. A nice 30 mile ride, get the bike completely warmed through and through. Then, if the idle is still hanging, find a nice safe place to pull over and turn them out a quarter turn. Keep riding and adjusting as required. If you get to the point that the idle starts to dip or wants to die, turn them in a eighth to a quarter turn.

Are you certain and I mean absolutely certain, bet a paycheck on it certain, that the jetting is correct ? I thought mine was.. only to disciver that they actually weren't, installed the correct jets and the bike came alive !!

[jimfj]

You might have an air leak as others have said. How is the airfilter and is the airbox sealed up tight. I fought this same problem and the cover to my airbox was leaking. Used stick on marine grade weatherstrip ffrom the hardware store and now runs like a dream.

Adjusting the mixture screws on my bike doesn't change the idle speed that much either. I used a Colortune and set them where the cylinder burn was best and left them. Mine popped on decel something fierce and the needle shim took care of most of that.

Lastly and certainly not least. I have had bikes that were behaving as you have stated and getting a good synch cleared up the problem. You said you replaced a carb body and then bench synched. That will usually get her going but the fine tune is where you smooth out all the ripples. I did a synch on an 1100GL this past weekend and barely moved two of the synch screws and it was almost like the bike was new. You may have one or two of the carbs pulling alot more than the others. Anyone who has done this will agree that to change the pull on the rack of carbs you aren't moving the screws much at all.

Let us know how you are getting along.

Jim

[atvpyrofreak]

just thought I'd mention that I'm fighting the same problem on a 85 GS700e. Just went through the carbs completely, new o rings in the carbs and intake boots. Everything cleaned thoroughly. Vacuum synced. Valves adjusted (before sync). Plugs indicate a little lean, and idle hangs around 2000-2500. On cold start up (with the idle set where it ran well when hot) it will not idle without choke. I know how confused you feel!

[Nessism]

On my old 550T the idle would hang until the mixture screws were set to 3 turns. 2 turns could be too lean. Also, bench sync is not good enough, you need to vacuum sync. Miss adjusted sync can cause the idle to hang as well.

[chef1366]

Sounds like the throttle linkage is getting stuck.
Check the boot clamps to see if they are in the way of the throttle linkage.
Make sure the throttle cable is adjusted properly and not sticking.

[swedge61]

The throttle cable was the first thing I checked. I had a problem once before when I turned hard to right it would cause a bind in the cable and increase the rpms. The cable now has a little slack in it. When the idle hangs I have shoved down on the linkage and it would not move.
One odd thing is if the idle hangs and doesn't come back down to idle, I can hit the choke and it will drop down to idle almost immediately.
Would the float height cause a hanging idle that gets worse as the bike gets hotter? I adjusted the floats up from around 20 or 21mm to 22.4mm
I am going to look at the airbox next. Bench syncing is the best I can do right now. I have no money for any extra tools.
Thanks for all the replies
Swedge61

[Nessism]

The throttle cable was the first thing I checked. I had a problem once before when I turned hard to right it would cause a bind in the cable and increase the rpms. The cable now has a little slack in it. When the idle hangs I have shoved down on the linkage and it would not move.
One odd thing is if the idle hangs and doesn't come back down to idle, I can hit the choke and it will drop down to idle almost immediately.
Would the float height cause a hanging idle that gets worse as the bike gets hotter? I adjusted the floats up from around 20 or 21mm to 22.4mm
I am going to look at the airbox next. Bench syncing is the best I can do right now. I have no money for any extra tools.
Thanks for all the replies
Swedge61

Did you at least try 3 turns out on the mixture screws? Pretty easy trial and nothing to loose. Regarding the sync tool, you might want to complete your profile so people can see where you live, there might be a GSR member near that can help you out.

[swedge61]

I am now at 3.5 turns out and still having the problem. I went to 3 first then 3.5.I will complete my information.
I live Louisville, Ky by the way.
Swedge61

[TheCafeKid]

That seems awfully lean to me unless the pilot jets have been changed. I would expect 1.5-2.5 turn out with stock pilots.

If he's running a stock set up, I wouldnt expect the .75 turns out to be all the remarkable... Remember these were set pretty lean from the factory. Just for kicks, the last few sets of stock UNTOUCHED carbs ive done ive pulled the adjustment screw plugs on and counted what the factory had them set at. On the SAME SET of carbs, ive seen one carb be 2 turns out, another be .75 turns out, yet another at 1 turn out, and the last be 1.75 turns out. They set them for what made the bike run the best at the time of production, and still kept it within the regulatory specs thru the rev range. And, as Ed has said, 2 turns could be JUST not enough, and 2.25 be perfect. When I was finishing up Chris Riddle's bike (Mike Riddles son...550ES) the bike simply wouldnt idle with the screws 2.5 turns out, I was getting very angry, because id gone thru everything else repeatedly. Then on a whim i turned them all 3 turns out, and it fired right up and ran like a champ. They can be very finicky, confusing and totally illogical peices of equipment sometimes...LOL

IF you are already three turns out, you might be best to pull the carbs again as Ed has said. It sounds as if you have some clogging still in the pilot circuit. When you take them down again, record what jet sizes you have in each carb, its possible someone has messed with them in the past? Make doubly sure that your cleaning out your pilot jets with carb spray, air, and fine strands of copper wire thru all of the jet holes, as well as spraying out the passages with carb spray. If the carbs werent properly rinsed after dipping, and carb spray and or air not used in the passages, that dip turns into some gooey crap when its allowed to dry.. ALSO, double check your FLOAT LEVELS. These are very important for proper idle as well. If they are not allowing enough fuel into the bowls, you will have these symptoms as well...

[swedge61]

I dipped the carbs, ran a wire through every hole I could find, Used about one can of carb spray per carb, making sure when I sprayed in one hole it came out somewhere else. Then I used my air compressor to make sure nothing was left in them.
I took a magnifying glass and checked the jets and compared the marking to what was in one of the post about what was stock in the carbs and everything matched.
I am beginning to suspect the float levels because they were changed from when the bike was running before this mess started but I can't figure out how they would affect the idle that much and get worse as the engine gets hotter.
Swedge61

[TheCafeKid]

Dumb question perhaps, but did you try turning the idle speed adjuster down once the bike was warm???

[swedge61]

When the bike is cold it will idle at 1000 rpms and hang for a split second at 2000 rpms on it way down to idle if reved up. After it gets hot it will idle but if you raise the rpms to around 3000 it will hang and stay between 2500 and 3000. Sometimes it will come back down to idle speed or if I hit the choke it will drop right down to idle speed.
I will try moving the idle adjuster out when it hangs to see what it does. I will try anything now. Well almost anything
swedge61

[gs_schmuck]

Sticky carb slides?







.

[swedge61]

The slides can be lifted easily and drop down smoothly. No sticking that I can see.
Swedge61

[almarconi]

I can't figure out how they would affect the idle that much and get worse as the engine gets hotter.

The float height effects all the circuits. You should also verify the fuel level in the bowls.

Since the idle drops when you add choke this would suggest to me that you are lean on your pilots. This sort of makes sense since the screws were only open about 3/4 of a turn. When you replaced the pilot screws was the rubber washer, metal washer and spring installed on the screw?
The order should be spring, metal washer and then rubber washer.