Project: 1985 GS550ES

[MelodicMetalGod]

Countdown begins: 12 days until temp tags expire

Countdown begins: 12 days until temp tags expire

And I still have no idea why the bike idles high after warm up. Anyone?

 

[LeeGS550E]

I read back a bit and found that you were thinking of replacing your boots, but it sounds like you haven't done that. There are o-rings on the underside of the boots where they meet the head. I recommend you at least replace the orings. Plus, switch out the philips head screws that attach the boots to the head for some socket head screws - you can get those boots torqued down better this way. You said you are using WD-40 to do your test for leaks. Try using Simple Green in a spray bottle - get everything dripping wet with the stuff while the engine is hot and running. Cover the boots, carbs, the whole area. This will give you more complete coverage than WD-40.

 

[zig06]

And I still have no idea why the bike idles high after warm up. Anyone?

If your bike is really warmed up, and it's completely off the choke but still has a high idle, then it's just a simple fact that your base idle setting is too high.

Have you tried to lower the basic idle setting?

 

[MelodicMetalGod]

If your bike is really warmed up, and it's completely off the choke but still has a high idle, then it's just a simple fact that your base idle setting is too high.

Have you tried to lower the basic idle setting?

If you're referring the idle set screw adjustment, yes. The set screw is backed off as far as possible.

 

[t3rmin]

Is your throttle cable too tight so it's pulling on the carbs at rest?

 

[MelodicMetalGod]

Is your throttle cable too tight so it's pulling on the carbs at rest?

Negative. I've added more slack than spec and checked to ensure that the throttle valve snap back all the way on the carbs when the throttle grip is released.

 

[MelodicMetalGod]

Spark Plug Reading

Spark Plug Reading

Here's a pic of my plugs:

According to the following images,

http://www.gnttype.org/techarea/engine/plugs.html

I'm thinking that the read is that my plugs are in the early stages of carbon fouling.

Would you agree?

Thanks for your time!

 

[Schweisshund]

Sea Foam Deep Creep

Sea Foam Deep Creep

Hey there - get some seafoam deep creep from advance or autozone. Saturate your carbs (one at a time) and after saturation, restart and stand back (the smoke is normal). This will completely clean out the carbon (do this when engine is hot).

rinse, lather, repeat. You should see results immediately.

 

[Schweisshund]

deep creep

deep creep

to be more specific - warm up engine - take screw out of boot closest to engine on one set of carbs - saturate with deep creep (loosen boot near air box saturate that end as well) then restart engine and stand back - it will smoke for a long long time (prepare to replace spark plugs if needed after this) , then do the same process for other set of carbs.

get your carbs adjusted/syncronized if it still idles high - one or two is out of sync.

 

[Nerobro]

the high idle is from the either a carb boot leak or the pilot jets. When they're lean the bike will do that.

 

[MelodicMetalGod]

to be more specific - warm up engine - take screw out of boot closest to engine on one set of carbs - saturate with deep creep (loosen boot near air box saturate that end as well) then restart engine and stand back - it will smoke for a long long time (prepare to replace spark plugs if needed after this) , then do the same process for other set of carbs.

get your carbs adjusted/syncronized if it still idles high - one or two is out of sync.

Actually, the carbs are recently cleaned throughout. I believe the plug condition is a result of tuning issues. Do you agree with my read on the plugs?

 

[MelodicMetalGod]

the high idle is from the either a carb boot leak or the pilot jets. When they're lean the bike will do that.

I was hopin' you'd have a chance to drop by. At this point I'm working on the air leak theory b/c a) it is such a prevalent issue and b) with the carbs recently cleaned (special attention on the pilot jets), it seems unlikely that their gunked again already.

Do you agree with my assessment of the plugs?

 

[MelodicMetalGod]

Airbox Boot Seal

Airbox Boot Seal

Learned something new last night: Airbox boots are not permanently attached to the airbox. Wish I'd know that before. Live and learn.

When I pulled the boots from the air box I found that there was dried "something". Is this just "gunk" or is it the remnants of a sealant? If a sealant, what sealant should be used?

 

[Schweisshund]

I have a 1983 Nighthawk CB 700 SC that did the exact same thing you are describing. High idling. It would actually idle at 2,000 rpms when cold then shoot up to over 5,000 rpms and stay there. I could not figure out what it was and took it to a friend of mine who used a mannometer (sp?) to synchronize each carb. That did the trick. Each jet needle has to have the same vacuum pressure if my understanding is correct. There were 4 on my Nighthawk and there are 4 on my GS 550 E.

You might want to see if your carburator linkange is bent as well. OEM?

 

[MelodicMetalGod]

I have a 1983 Nighthawk CB 700 SC that did the exact same thing you are describing. High idling. It would actually idle at 2,000 rpms when cold then shoot up to over 5,000 rpms and stay there. I could not figure out what it was and took it to a friend of mine who used a mannometer (sp?) to synchronize each carb. That did the trick. Each jet needle has to have the same vacuum pressure if my understanding is correct. There were 4 on my Nighthawk and there are 4 on my GS 550 E.

You might want to see if your carburator linkange is bent as well. OEM?

Well, I've done the bench syncing. Once the carbs are back on and I've looked at all the air leak stuff, I'll defintely have to properly sync the carbs given your experience. Thanks.

 

[Schweisshund]

Noticed your from MD - DC area. I went to Gallaudet University for 6 years (am deaf) on Florida Ave NE :-D I know a deaf mechanical wiz in Laurel named Dusan Jaksic whom may have a mannometer. I also heard one person say you can use propane to tell if there is a leak in your boots (I wouldn't try it myself though). The concept is to turn the gas on while the engine is running and place the gas near the boots, if the engine fires rapidly then there is a leak. I wouldn't want to find out the hard way if the propane gas ignites (I don't understand enough about it to try).

 

[MelodicMetalGod]

Noticed your from MD - DC area. I went to Gallaudet University for 6 years (am deaf) on Florida Ave NE :-D I know a deaf mechanical wiz in Laurel named Dusan Jaksic whom may have a mannometer. I also heard one person say you can use propane to tell if there is a leak in your boots (I wouldn't try it myself though). The concept is to turn the gas on while the engine is running and place the gas near the boots, if the engine fires rapidly then there is a leak. I wouldn't want to find out the hard way if the propane gas ignites (I don't understand enough about it to try).

Yep, I know Galludet. I've been by there many times. I was always fascinated that they had a football team and I learned that they used a drum to "call the snap"...I still think that's genius!

I don't think I'll be going the propane route. :-| I'm currently replacing the intake boots and o-rings as they're the likely culprit. I aslo need to address the union of the air box and boots. After that, I'll get into the finer carb tuning and I may very well contact you about getting in touch with Dusan Jaksic. Thanks!

 

[Nerobro]

No, your plug read is off. Your plugs are slightly white. That means lean, which indicates carb boot leak. Did you replace your carb boot o-rings? The ones I pulled off of my 83 cracked when they fell to the ground. They were D E A D.

 

[MelodicMetalGod]

No, your plug read is off. Your plugs are slightly white. That means lean, which indicates carb boot leak. Did you replace your carb boot o-rings? The ones I pulled off of my 83 cracked when they fell to the ground. They were D E A D.

In the process now. I've gotten the old ones off. However, neither the boots or the rings look particularly bad. As far as I can tell, the rings are bit flattened (as you'd expect) but everythings still pretty soft and maleable. Next session I'll be putting the new stuff on and doing everything I can to seal as I go.

 

[Jagir]

I also heard one person say you can use propane to tell if there is a leak in your boots (I wouldn't try it myself though). The concept is to turn the gas on while the engine is running and place the gas near the boots, if the engine fires rapidly then there is a leak. I wouldn't want to find out the hard way if the propane gas ignites (I don't understand enough about it to try).

I tried this and it didn't tell me anything, but my leak was on the vacuum hose.
Have you replaced your hoses with clear ones? The local shop just gave me a few short lengths of this to replace my old black ones. This will help you diagnose.
good luck
j