All possible vacuum leak locations

[timebombprod]

Back on, everything is working great all through the powerband and it idles with all 4 cylinders operating. But I wouldn't be here if everything was operating correctly.

The bike likes to hang at around 3-4k time to time, and usually I'd be able to just pull the choke and it'd drop back down to idle speed, but now it wants to keep jumping back up nomatter what, if I turn down the idle it gets somewhat better but still will go up either way.

I've replaced the intake boot rings but I'm gonna get another set to be safe, but where else could this come from? If the main seal for the two airbox pieces was leaking would it do the same? Or is there certain spots that will cause the high idle of leaking.

Also could anything else cause this to happen?

[timebombprod]

Does it make a difference if it only happens in neutral or the clutch pulled in

[GregT]

Does it make a difference if it only happens in neutral or the clutch pulled in

No.

Pull the carb tops off and carefully lift the diaphragms and slides out. Check for tears in the diaphragms. Ensure the diphragm edges are seated correctly when you replace them.

[timebombprod]

If the diaphragms are okay, would there be anything to check with the slide mechanism itself? Gonna check the diaphragms possibly tonight ifnot forsure tomorrow aswell as rechecking for vacuum leaks as my bike is loud and I live in the suburbs.

I will say my bike kinda bogs a bit before I'm off and running, but still I needa check this stuff either way.

[timebombprod]

Can this be the culprit? Ifso, the good news is it's only one, heard these go for like 100 or more a piece for the assembly but i also heard people have had success just gluing on a new membrane, I can have surgeon hands!20210225_013018.jpg

[timebombprod]

Wiped all the diaphragms down especially around where it seals gonna see tomorrow if that makes a difference

[timebombprod]

Heres how it ran today, I'm gonna have fuel levels done again as I messed with one (shouldn't have) and its no harm just getting all 4 done.

I sprayed wd40 on the intake boots and no noise change other than a cylinder coming in and out, so it's actually hard to tell, I'm gonna have to do a recheck after the fuel levels to get an accurate response, but I'll be ordering those intake boot rings either way.

I noticed my bike makes a chirp from the engine and what it sounds like is when you turn your bike off and the cylinders slowly stop moving, I noticed when the chirp happens the idle moves down just a bit, but it seems like the bike is cutting out in a sense but it doesnt shut off, never had this before.

Heres the vid from today, all 4 headers were steaming hot when I did a water test.

https://youtu.be/1qEZNfiQbUc

When i checked timing on this bike a little while back, it went way past the F but i believe aslong as the mechanical advance was responding that the timing is fine. Educate me if otherwise.

[timebombprod]

Disconnected throttle cable today seeing if that was getting stuck, well it wasnt.

Made two discoveries, I only have that chirp when the bike is up to temperature, and i only have that idle hang also when the bike is up to temp.

Gonna get a video of the chirp/skip and possibly drop the oil pan to see if there's any metal shavings or whatever.

[timebombprod]

Disconnected throttle cable today seeing if that was getting stuck, well it wasnt.

Made two discoveries, I only have that chirp when the bike is up to temperature, and i only have that idle hang also when the bike is up to temp.

Gonna get a video of the chirp/skip and possibly drop the oil pan to see if there's any metal shavings or whatever.

Made a video, you can barely hear it but I'm gonna upload and give the time frame it happens, doesnt happen every revolution, it's pretty random, and has an inconsistency of how loud it is. So good time to drain the oil and check if theres something.

[timebombprod]

Heres the video go to the 18 second mark and the noise is at 20-21 second mark. After that I just talk about it for a bit and what I'm thinking of doing for the hanging idle issue. The noise is a bit subtle but should be heard if you pay attention.

https://youtu.be/jZwOxKrCUBY

Actually, this video shows the sound better, it skips more so than chirps you can hear it clearly in this one

https://youtu.be/1qEZNfiQbUc

[daniel3332]

What happened?

So what ever happened with this? I have an 83 GS550 with very high idle and similar issues, thinking I have a vacuum leak somewhere as well.

Heres the video go to the 18 second mark and the noise is at 20-21 second mark. After that I just talk about it for a bit and what I'm thinking of doing for the hanging idle issue. The noise is a bit subtle but should be heard if you pay attention.

https://youtu.be/jZwOxKrCUBY

Actually, this video shows the sound better, it skips more so than chirps you can hear it clearly in this one

https://youtu.be/1qEZNfiQbUc