Help diagnose my choke/idle problem from this video.

[Toner]

Hi guys, please have a look at this video:

The bike has been warmed up and driven for about 15 minutes just so I'm not showing you a cold start. It does this for cold starts too.

You can see its idling at 1500 to begin with. 
Then I open the choke up all the way and it increases to 4000.
The I close the choke half way and it stays at 4000 or even increases a little.
Then I close the choke completely and it goes back down to just above 1500.
Then I open it halfway again and it dips to 1000 this time.
Then I open it all the way and it comes up to 4000 again.
Then I close it halfway and the RPMs go up to 4500

When driving my bike and I stop at lights, sometimes it will idle at 1000 and I'll have to give it some juice so it doesn't stall and sometimes it will idle at 1500.
When I start it up cold, sometimes it is a struggle to get it above 1000 before I take off.   

From that vid, would you be able to tell whether it is a carb problem or something else? perhaps the petcocks or fuel lines maybe?

[Watcher]

Can't watch the video right now but it can be fairly easy to diagnose idling issues.

To rule out fuel set the petcock on PRI and see if that changes any behavior.

Fill a spray bottle with water and mist it around the carbs when the bike is idling, if there is a vacuum leak it will draw the water and the idle will fall or the engine will stall.

Of course there's always the chance your choke is improperly set, and when you think it's off it's really on slightly.  Make sure the choke moves freely on the carbs and that there is a little bit of slack in the cable when the lever is all the way off.
A quick check for proper slack is to turn the bars from full lock left to full lock right and see if there is any idle change.  Assuming, of course, the throttle is properly set.

[mr72]

My bet:

>1 vacuum leaks
Pilot mixture too too lean
"Idle speed" too high

Fix vacuum leaks first. While carbs are apart (because you are replacing all o rings in the process of fixing vacuum leaks) put a bigger pilot jet if you haven't already increased it from stock. Then set the idle speed after riding on the road for 20+ minutes, 1200 RPM.

See my blog for details on how to sort this all out. Going through this process is quicker and far more effective than trying to troubleshoot and fix one problem at a time.

[Toner]

Can't watch the video right now but it can be fairly easy to diagnose idling issues.

To rule out fuel set the petcock on PRI and see if that changes any behavior.

Fill a spray bottle with water and mist it around the carbs when the bike is idling, if there is a vacuum leak it will draw the water and the idle will fall or the engine will stall.

Of course there's always the chance your choke is improperly set, and when you think it's off it's really on slightly.  Make sure the choke moves freely on the carbs and that there is a little bit of slack in the cable when the lever is all the way off.
A quick check for proper slack is to turn the bars from full lock left to full lock right and see if there is any idle change.  Assuming, of course, the throttle is properly set.

Cheers Watcher, on PRI the bike had the same behaviour.
I sprayed some ignition fluid around the boots before and I didn't notice the revs change. 
Turning the bars did cut it off once but not every time. It could be the choke cable. Might take the tank off again and look at that before I attempt a carb job at a later date.

[Toner]

My bet:

>1 vacuum leaks
Pilot mixture too too lean
"Idle speed" too high

Fix vacuum leaks first. While carbs are apart (because you are replacing all o rings in the process of fixing vacuum leaks) put a bigger pilot jet if you haven't already increased it from stock. Then set the idle speed after riding on the road for 20+ minutes, 1200 RPM.

See my blog for details on how to sort this all out. Going through this process is quicker and far more effective than trying to troubleshoot and fix one problem at a time.

Cheers for the link m472.
That suggested two hours of work looks like a 2 day-er for me. I'd be back and forth looking up carb cleaning guides, reading the manual and probably asking questions here as I go through it. 

Hoping it's not the carbs but if it is, it is and I guess your advice is just to change everything.  I guess I was going to have to do it eventually. 
Took a second video today in the day light: 

The behaviour is fairly consistent: 

The bike is fully warmed up here.
You can see it idling at about 1500 RPM.
I open the choke up half-way and the revs drop to ~1000.
When I subsequently close the choke, they go to 1700.
Then I open the choke all the way and after giving it some throttle, I can get them up to 4000.
Closing the choke halfway this time increases the revs to 5000!
Then closing the choke all the way returns the revs to ~1700

Might this behaviour happen if one of the needles was damaged?
Don't know too much about carbs but I thought I remembered someone saying that different needles deal with different rev ranges and so perhaps a needle dealing with the 2000-4000 range is damaged?

Think I'll check the choke cable out first before I do a carb job if nobody knows. 

[user11235813]

I agree the air/fuel could be a bit lean. I have seen that it's easy for the chock sliding arm on the carb to get a little sticky. You should be able to see that the plunger goes all the way in, maybe put some wd 40 around the sliding parts. The choke does tend to get fast quickly.

[Toner]

Good News.

I think it was the choke. 
I took it out of its housing and re-installed it.
The choke cable was routed through the breather tube and another cable so I routed it under both of them instead. 
Not sure if that was it.
I also greased the choke cable nipple before putting it back in and greased the metal sheath/tube or whatever you call it that goes into the housing too. 
Not sure if that was it either. 
The spring wasn't sitting right either but I don't think that was it. 
Whatever it was, the choke seems to be acting right now but I haven't brought it for a spin as it's dark and probably icey out.
I'll take the bike out tomorrow and check it out fully. 
Cheers for all the help. This forum is invaluable. Owning a GS would not be the same without it. 

[Toogoofy317]

Mine is doing almost the same thing. Gonna get some gaskets for the carbs. But, currently in the hospital.

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