dying below around 1400 rpm. video attached

[Guest]

Heres the story, I had extra time yesterday to pop the carbs back in. Once I did I hit the magic start button and pulled up the choke and vroom, she fired right up and sounds really nice. It was getting dark out and the battery was low so I hooked it up to the charger and let it sit for the night.
Today after work I grab the battery out of the garage and plug it in, and she fires up nicely again. Here is the interesting part, after a minute or so the idle starts rising (I assume this is normal) so I push in the choke a small bit and it controls the idle nicely. It starts rising again so I push it in more. Each time I control it to about 1400rpm. whenever I try to drop it down to the 'normal' 1000-1200rpm it falls off and dies.

My question is what can be causing this? I have my valve cover gasket(current one has quite a few leaks in it) in the mail and plan to switch out some rotella this weekend, so if that may make things different, well Ill check back then....

as promised, here is the video. Its more of a sound clip with some visual aid, but I hope it helps

http://www.facebook.com/v/1713656397458

If the video doesnt work, Ill try reloading it to photobucket or youtube. Thanks in advance for any help and advice you can give.

ps: I post this in the carb/intake section because it seems to be affected by the choke, but I am not sure if this is the root cause.

[BassCliff]

Hi,

The video did not embed properly.

Have you properly cleaned the carbs? Which of the following have you accomplished?

Common Issues:

1. Intake O-rings (install NEW OEM or Viton only - common nitrile O-rings will quickly deteriorate from heat)
2. Intake Boots (install NEW -- these cannot be repaired)
3. Valve clearances (more important than most people think)
4. Carb/airbox boots
5. Airbox sealing
6. Air filter sealing
7. Petcock (install a NEW one)
8. On '79 models, install new points or Dyna electronic ignition (or at least verify that the old points are working correctly)
9. On all models, it's fairly common to have problems with the spark plug caps. These are $3 or $4 each, and often worth replacing if you're keeping the stock coils/wires.
10. Stock exhaust with NO leaks or holes -- good seals at the head and at the junctions underneath.

Brian's E-Z and fun plan for GS happiness:

1) Seal the airbox and air filter with weatherstripping.

2) Ensure no intake leaks. Spraying WD-40 or water doesn't tell you much, since very small air leaks can cause problems even though they won't suck in enough WD-40 to make a difference. Replace your intake boot o-rings and boots if needed, and seriously consider spending the lousy $28 for new airbox/carb boots.

3) Ensure clean carbs with correct settings, new o-rings, and original OEM jets. No, not just squirted with something. I mean completely disassembled.

4) Check/adjust valve clearances (Manual calls for every 4,000 miles. This is not optional.)

5) Ensure healthy electrical system.

6) Seriously consider upgrading coils and plug wires.

7) Install new, stock NGK B8-ES plugs gapped to .031".

8 ) Fine-tune float height and idle mixture screw to ensure best off-idle transition.

9) Clean air filter and reinstall with only the lightest oil mist -- over-oiling and/or letting the filter get dirty is a common and critical mistake, and will make the bike run funny at low speeds and run rich. This may take a few tries.

10) Make sure the exhaust seals are sealing.

11) Ooh, much better now, huh? You're gonna need upgraded suspension - Progressive or better fork springs and shocks. Set suspension sag appropriately.

12) Upgrade brakes with new pads and stainless lines to deal with all that extra speed.

13) Install new petcock, since I'm going to head to the roof with a rifle if I have to read about yet another #2 plug fouling and failed hillbilly attempts to rebuild the petcock and/or deny there's a problem.

14) Oh yeah -- check compression somewhere in there to ensure the valves and rings are reasonably healthy.

15) You'll probably need new OEM clutch springs -- the clutches last forever, but the springs get tired after 20 years or so under pressure. E-Z and cheap.


Thank you for your indulgence,

BassCliff

[JCSkokos]

1. check
2. check
3. check
4. check
5. its iffy, I am probably going to pick up some weatherstripping when I make my trip to Wal-Mart
6. check
7.The old one seems to be working fine other than some sticking when moving from prime to on or on to res
8.N/A
9. Again, these seem to be working for now, all cylinders fire.
10. All seals are in good condition and the pipes are visually in good shape.

#2: the o-rings were replaced when I got the carbs done.
#3: the carbs were just rebuilt and cleaned. new o-rings and the whole bit.
#5: I am going to replace the stator with the oil change.
#8: I really think I have to adjust the idle screws, but with the choke open I dont think it does too much. Does it?
#9: I also have a feeling I over oiled it. I used the UNI spray oil and I hear its extremely easy to over oil. What are some symptoms of over oiling the filter?
#13: none of the plugs are fouling and like I said, the petcock's only issue is that it is hard to turn the knob.

I just noticed the video too. The blue links work, but for some reason it didnt embed.

[waterman]

Try adjusting idle speed up a bit. It may be that you have it set too low and the choke is feeding enough fuel to keep it from stalling.

Then once you can get it to idle, even at a higher than normal speed with choke off, adjust your mixture screws for the highest maximum idle on each cylinder. Then try to readjust idle speed back to recommended level.

[JCSkokos]

Try adjusting idle speed up a bit. It may be that you have it set too low and the choke is feeding enough fuel to keep it from stalling.

Then once you can get it to idle, even at a higher than normal speed with choke off, adjust your mixture screws for the highest maximum idle on each cylinder. Then try to readjust idle speed back to recommended level.

OH JEEZ! Thank you! I just remembered I turned the big screw all the way out before I put the carbs on yesterday. I will try turning that in as soon as I get back out there. That makes a lot of sense now.

correction; Ill try it tomorrow, the battery is low again.

[Theamania]

First off i would like to say Thanks everyone for a great forum.
I just bought my first bike, and after lots of research i picked up a Gs 550 Katana this week. Been standing for a while but its slowly coming back to life.

Anywho, JCSkokos.. You seem to already have found the error being the idle screw, but i thought i'd share that i had the same problem.
My bike has the same symptoms, lowering the choke and the idle rpm goes way down until it dies. I have fiddled with the idle speed, and it stays alive, altho the Idle can go up to 2500 rpm after revving.

What i found was that for some reason, its the battery.
When i have a fresh car-battery connected with jumpercables it works perfectly. But the battery in the bike is really dead (wont turn over the starter)
Since you said you had charged, and that battery is dead again i thought i might give you, or someone else, the tip: check the battery, its a clean, quick easy thing to do

Thanks
/TJ

[JCSkokos]

Its a new battery, but the whole thing with starting and re-starting to fiddle with it wears down the charge. The stator being bad doesn't help much either.
Its still giving me trouble, but I was going to wait till I had all the gaskets replaced and fresh oil in the motor before messing with it more.