stalling

[niko]

hi all,
im having a problem with my gs550, it runs great through a ride, i can run all over town, then at random as i am coming up to a light it will sputter, idle drops and if i dont bump the throttle it will stall, sometimes it will also dip below 1100 rpms coming up to a stop and then catch itself, ive done most of the obvious reccomendations from this site, since when i got it it didn't run at all, ie cleaned/dipped carbs, checked valve clearance, air filter, r/r, new old igniter, went through electrical connections although the plug wires/coils are old and questionable, and i just bought a new negative battery cable that i havent put on yet. i think it is running slightly lean, as the plugs look tan but maybe a little grayish near the tip, i gave the fuels screws another half turn and that seemed to help a little, but the thing is that it runs and idles perfectly most of the time and then at maybe one stop in thirty or forty will sputter and/or stall. also it idles at 1100 with the thumb screw on the carbs all the way out so it isnt opening the butterflys at all...

thanks for your thoughts

edit - once idle drops below 900 or so the gauges will flicker in time with the engine...

[hikermikem]

Check the plug wires & caps are good - perhaps replace the OEM caps with NGK ones...

Check the colis are not intermittently grounding out against the frame through the mounting bolts - I had that issue with the same bike.

Something doesn't sound right about the idle knob if you say it doesn't do much ??

Good luck,

Mike

[niko]

the knob works but at 1100 rpm it is turned completely out, i checked resistance on the coils and plug wires and the numbers checked out, but i am still wondering if they are intermittently causing a problem, how did you fix the grounding problem?

[Nessism]

Have you vacuum synced the carbs?

[Griffin]

You may have two things going on here, based upon your description of two different issues.

For the stalling thing, have you changed out the intake boot o-rings? My 700 was doing precisely that after I pulled it out of a seven year storage. Drove me nuts, thinking it was carbs, then ignition. Finally changed out the intake o-rings,a nd the problem magically went away. Spray some WD-40 into the intake boot area while idling, and see if rpms change.

As for the low rpm light flickering, check voltage across the battery terminals from 800-5,000 rpm. It should exceed 13-13.5v somewhere around 1,500-2,000 rpm, and then pretty much steady out in the 13.5-14.5 range to infinity. If it doesn't, you have a regulator or stator issue.

That wouldn't really cause the stuttering idle issue.

[niko]

i haven't vacuum synced them yet, i bought the equip to make a manometer today, but havent put it together yet, i did bench sync them, and its not happening all the time which is what's throwing me off, if it is a sync problem shouldn't it happen all the time

[niko]

boots are in good shape, no leaks when i spray around the carbs/intake anyone know where to get orings besides robert barr, he doesnt have a set up for my bike.

[Griffin]

boots are in good shape, no leaks when i spray around the carbs/intake anyone know where to get orings besides robert barr, he doesnt have a set up for my bike.

www.babbittsonline.com



As for the idling with the adjustement screw turned all the way out, the fuel/air mixture screws can accomplish that themselves if they are turned too far out.

[hikermikem]

...anyone know where to get orings besides robert barr, he doesnt have a set up for my bike.

You can get the o-rings from Robert, I have the same bike/carbs & I used the CV kit from him. There will just be extra o-rings as compared to the 4 barrel set-up.

He doesn't list that bike because those 2 barrel CV carbs are different from the standard 4 barrel he's used to...

I think you want the large sized intake o'rings, but maybe just buy both the large & small sets to be on the safe side - they're cheap enough...

Don't remember the bolt dia or length on the intake boots, but make sure you replace them with SS allen heads. I seem to remember one or two of them were shorter than the rest? Good luck removing them - might as well rebuild the cam chain tensioner while you're there if it looks like it's been leaking a little oil. Mr. BikeCliff's web site has a great little tutorial for that...

good luck,

[niko]

thanks for all the input i definitely have a few more things to try, and ill put in an order with robert, i appreciate everyone's help

[jjmaag]

Is your throttle or choke cable length set too tight and holding the butterflies or choke circuit open enough that your idle won't drop below 1100RPM?

[niko]

no they close completely, i got the rack of carbs off of ebay and im wondering if thery are jetted differently, i thought that i had compared that when i rebuilt them, but it was last summer and im not entirely sure, they definitely are the same carb bodies.