Idles when choked, shuts off when not

[JStones]

1980 SUZUKI GS 550L

For those of you who arent familiar with my electrical posts. This bike sat for 4 years. I bought it a month ago. I tore it down and cleaned it up. Carbs were cleaned properly. New Petcock. New Battery.

I got the bike started for the first time last night. It idled rough to start and then got progressively better. Working out the kinks, hadnt run in years was my thought. Anyway, It would run on full choke and even half choke but thats it. I let it run for a good half hour before calling it a night. What would be causing this?

[niclpnut]

Did you adjust the idle screw to up the idle when you take off the choke?

Mixture screws set proper turns out?

[Nessism]

Hope you had a fan blowing on the engine, 30 min. is WAY too long to run the bike without airflow.

Regarding the running problem, did you install the airbox?

[JStones]

Airbox installed. Fan was used to induce some air and keep it cool.

Can you give me any tips with the idle screw? I am aware of it, although I did not adjust it at all.

[Steve]

Can you give me any tips with the idle screw? I am aware of it, although I did not adjust it at all.

Turn it clockwise until it idles at the proper speed.

Now back to niclpnut's question, where are the mixture screws set?

Did you do a bench sync to get it running good enough that you could procede to a vacuum sync with gauges?

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[Nessism]

T

Now back to niclpnut's question, where are the mixture screws set?



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Yes, this is the question. In order to clean the carbs the screws must be removed.

[JStones]

Hey guys, just had a child been out of the game on this. Anyway, screws are set to 2 turns out per the Specifications within the manual. Any tips from here?

[Nessism]

I'd set the pilot screws to 3.5 turns open and vacuum sync the carbs.

[Steve]

Hey guys, just had a child been out of the game on this. Anyway, screws are set to 2 turns out per the Specifications within the manual. Any tips from here?

Very interesting. I have never seen anything in any of the manuals about setting these screws except "DON'T TOUCH THESE SCREWS".

2 turns might not be quite enough. Nessism just suggested 3.5 turns. I usually suggest 3 turns. These are both STARTING POINTS.

After the bike is warmed up, you will need to slowly turn the screws (probably IN), listening for highest idle speed. If speed does not increase, keep turning until the speed starts to decrease, then back out about 1/8 turn. You may find that they end up about 2 to 2.5 turns out, but will run poorly enough at only 2 turns, you will experience the problems you are reporting. Starting at 3 turns or more is also acting a bit like a "choke", enrichening the mixture for easier cold starting. Once you get them properly adjusted, you may have to use the "choke" for a few seconds to start a cold engine, but will be able to ride within a minute and turn the "choke" off by the time you get into second gear.

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[JStones]

Well I am a bit confused then. My bike (to my knowledge) has 2 adjustments. The Idle screw underneath and the the mixture screws at each carb on top.

The manual references the mixture screws and says "refer to specifications for proper settings", from there I go to the specs and it says 2 turns out.

I dont fear that the advice you have given me is wrong. I fear I am the one is missing something here.

[cowboyup3371]

Set your mixture screws on top of each carb to 3 turns out at first. Then get your bike nice and hot (10 min ride is pretty good), set the idle using the adjuster below your carbs to about 1500, and adjust each one until you can hear the idle change. Once that is all done, adjust your idle back down to about 1250.