so so puzzled

[richardgrhett]

so i have an 79 gs 550 just put new o rings on intake boots completely re-did the carbs adjusted the fuel and air mixture screws to the standard settings and the thing cranks up beautifully.......but it HAS to run on choke, continuously backfires out of #1, and whenever throttle is applied it dies..... PLEASE help!

[tkent02]

You are not getting enough fuel through the pilot circuit, so it only runs with choke. Mikuni choke is not a true choke but only an enrichment device which only works when the throttle is closed... So when the throttle is opened the choke stops functioning and the engine quits. Where did you set the fuel screws? Somewhere around a turn out from lightly seated is usually a good starting place, not sure about your model. Open your fuel screws farther, if that doesn't work perhaps the pilot circuits are blocked somehow.
Did you make sure the tips of the pilot fuel screws didn't break off in the carb bodies? That could be the blockage, they are easy to break off by screwing the screws in too tight.
The airscrews need to be adjusted to the highest idle method after the bike will idle.

[TheCafeKid]

79 550 have VMs or BSs on it?

[richardgrhett]

it has vm's on it...... i continue to back out the fuel screws and its running smoothe at half choke just continues to die when chokes cut off...?? im scared to back out the fuel screws too much....?

[richardgrhett]

the pilot circuits are clear and yeah the holes are all clear as well...iv got the air screws at two turns out by the way thx

[TheCafeKid]

Fuel screws are the ones underneath, air screws are the ones on the side, just so we're sure we're talkin about the same screws.

I dunno what your manual says, but with the fuel, i would suggest, somewhere in the 1/2 to one whole turn out range. Air, one and a half. Then go from there. I would guess that those are about the base settings. If you get much past 3 turns on either, i would stop.

Second question, is this bike stock? as in Original Airbox and 4into2 pipe on it? And did you adjust the valves?

[tkent02]

Are your fuel levels correct?

[richardgrhett]

havent touched the valves, the carbs have pods on them usually, right now nothing... yeah fuel on bottom air on top. id say right now im around 3 and a half turns out on fuel and 2 turns out on the air??

[richardgrhett]

fuel level as in float adjustment??? never messed with the floats

[TheCafeKid]

K most of your problem is that the carbs are NOT going to function properly with NO restriction at all on them (ie no airbox, pods etc.) You are now running the bike UBER lean. (Not good) no amount of tweaking the screws will fix this. Put your pods on, and then go from there. Secondly, before you do ANY adjustment to your carbs, you should check your valve clearances for any adjustment they may need. NOT difficult, provided you have a manual and the proper simple tools, and i do believe BassCliff even has a tutorial on it, should you not have a manual. His bike is an 850, but the process is identical.

Seriously, if you dont take care of the valves, youre going to go nuts trying to get the carbs right. If they arent adjusted properly, they can give symptoms similar to poorly operating or flowing carb issues. And again, these bikes will NOT run right without the proper air flow restrictions, or jetting to accomodate. If you dont know, your carbs need to have the proper size jets to accomodate pod filters as well, they are not plug and play devices More than happy to help, but there are certain things that need to be taken care of first, before you can begin to figure out what you're asking. :-D

[greg78gs750]

K most of your problem is that the carbs are NOT going to function properly with NO restriction at all on them (ie no airbox, pods etc.) You are now running the bike UBER lean. (Not good) no amount of tweaking the screws will fix this. Put your pods on, and then go from there. Secondly, before you do ANY adjustment to your carbs, you should check your valve clearances for any adjustment they may need. NOT difficult, provided you have a manual and the proper simple tools, and i do believe BassCliff even has a tutorial on it, should you not have a manual. His bike is an 850, but the process is identical.

Seriously, if you dont take care of the valves, youre going to go nuts trying to get the carbs right. If they arent adjusted properly, they can give symptoms similar to poorly operating or flowing carb issues. And again, these bikes will NOT run right without the proper air flow restrictions, or jetting to accomodate. If you dont know, your carbs need to have the proper size jets to accomodate pod filters as well, they are not plug and play devices More than happy to help, but there are certain things that need to be taken care of first, before you can begin to figure out what you're asking. :-D

+1 on all this. valves. filters on.

[richardgrhett]

well pods are back on and to no avail exact same dies out every time i turn the choke off... so im guessing its time to check the valve's?

[Ludeykrus]

well pods are back on and to no avail exact same dies out every time i turn the choke off... so im guessing its time to check the valve's?

You CAN try going back to base settings on the carbs and trying to set them from there now that the pods are on, but honestly you really should go ahead and check the valves before going any further.

[richardgrhett]

yeah im dreading it my manual does a terrible job on the clearance checks any suggestions on where to get the feeler gauges? and any tips in advance?? thanks alot

[greg78gs750]

i got a cheapie set of feelers at an auto parts place, in in., but with mm conversions printed right on the blade, down to .038 mm, which is plenty small. there is a thread on this somewhere recent, seems there is a nice snap on one avail pretty cheap online, but the el cheapo seems to work for me. i JUST did this. clean the engine up BEFORE you open anything up . it's easy. i used the "zip tie method" (again, search for this) and it seemed to work very well, without the special tool. and i am replacing my gasket with a realgasket, so i will never have to scrape that f****r again. dont overtorque the screws when you put them back on. plenty of info out there on this, check out basscliff's terrific website.