Brendan Posted August 16, 2020 Share Posted August 16, 2020 Hello, I was hoping somebody could help me out with the starting issue im having on my 1980 gs550l that I am currently restoring. So far the only way I've been able to start the bike is with starting fluid, but it absolutely refuses to start on its own. Once it starts, it runs good, but at idle it always drops in rpm until it stalls. When running, it is also slow to return to idle when it is revved up. The carbs are getting gas and the bike is getting spark. Any idea on what the problem could be? Air/Fuel mix? Bad coils? I appreciate any and all help and input. Thanks. Quote Link to comment
Gixer1460 Posted August 17, 2020 Share Posted August 17, 2020 Stop using Starting Fluid ! If it won't start without it, its a carb problem. If it runs 'Good' when it does start, then it can't be electrical! If you are restoring it - why are you trying to run it with dirty / non functional carbs......... get them properly clean and serviced then you may have more luck! Quote Link to comment
MeanBean49 Posted August 17, 2020 Share Posted August 17, 2020 11 hours ago, Brendan said: Hello, I was hoping somebody could help me out with the starting issue im having on my 1980 gs550l that I am currently restoring. So far the only way I've been able to start the bike is with starting fluid, but it absolutely refuses to start on its own. Once it starts, it runs good, but at idle it always drops in rpm until it stalls. When running, it is also slow to return to idle when it is revved up. The carbs are getting gas and the bike is getting spark. Any idea on what the problem could be? Air/Fuel mix? Bad coils? I appreciate any and all help and input. Thanks. Sounds like blocked idle jets, or far too lean on the mixture screws. Be worth taking the carbs off and giving them a good clean out and setting the screws to factory spec. 1 Quote Link to comment
wraith Posted August 17, 2020 Share Posted August 17, 2020 (edited) As @MeanBean49 and @Gixer1460 says, and balance the carbs after you've had them apart. Welcome to OSS by the way, also nice to introduce yourself in the general section before jumping in with questions, you get a nicer reply and don't forget we like pictures of Suzuki and project builds And RTFR in general section Edited August 17, 2020 by wraith 2 Quote Link to comment
Brendan Posted August 17, 2020 Author Share Posted August 17, 2020 Perhaps I should clarify some more with what has already been done. I have already taken the carbs off and cleaned them and the jets thoroughly so they are not dirty and non-functional, but I did not seaparate the carbs from each other in the process so they shouldn't need synced. I was hoping to get some insight on the issue before tearing the carbs apart again. Thanks for the any feedback. Quote Link to comment
MeanBean49 Posted August 17, 2020 Share Posted August 17, 2020 41 minutes ago, Brendan said: Perhaps I should clarify some more with what has already been done. I have already taken the carbs off and cleaned them and the jets thoroughly so they are not dirty and non-functional, but I did not seaparate the carbs from each other in the process so they shouldn't need synced. I was hoping to get some insight on the issue before tearing the carbs apart again. Thanks for the any feedback. Whether they have been split or not they will need balancing (sync'ing). If the jets are all clear, and the air ways to them in the carb inlets, I would guess either the mixture screws are set too lean (screwed in too far) or you have a huge air leak somewhere. Are you runnining it with no airbox/filters fitted? Quote Link to comment
Brendan Posted August 17, 2020 Author Share Posted August 17, 2020 Airbox/filter is attached. Would the mixture screw be in the float chamber or the brass screws on top the carbs by the manifolds? Thanks again. Quote Link to comment
wraith Posted August 17, 2020 Share Posted August 17, 2020 I think looking at them carb rubbers that's your problem, bet they're leaking 1 Quote Link to comment
Fazz711 Posted August 19, 2020 Share Posted August 19, 2020 On 8/17/2020 at 11:16 PM, wraith said: I think looking at them carb rubbers that's your problem, bet they're leaking Think he is right. The rubbers look past there best. 2 Quote Link to comment
BigT Posted August 19, 2020 Share Posted August 19, 2020 Failure to start and falling idle points to a valve clearance adjustment But, not discounting your carbs need cleaning and items need replacing on your 40 year old bike Go here https://www.thegsresources.com/_forum/showthread.php?171846-Top-10-Newbie-Mistakes&highlight=top newbie mistakes and here - http://zeus.mtsac.edu/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf Once you've completed all of that, report back. Don't do things the hard way, by cutting corners And, yes, those are your idle mixture screws on top at the front of your carbs 1 Quote Link to comment
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