1982 GS550L lean

[mizz0313]

okay! Thanks for all your help tom you have helped me learn this bike in a matter of a few months and by just a few post. Thanks for all your time and effort. Will keep you updated on this.

[mizz0313]

okay another update. tore carbs apart and dipped them again, bowls had little rust making its way through my old screen that had a slight tear(new petcock was installed but bowls weren't drained) . Another thing i kept avoiding was intake boots, looked okay and after purchasing new ones looking over old ones they were not okay and allowing air. installed cleaned carbs and new boots while carbs are also benched synced. Decided to take bike out to warm up before vacuum sync and it drove great, idle moved around a bit when coming to a stop and after turning it back down and going it continued on fine. Came home parked and let idle throttle was very responsive and came back down nicely to 2k, couldnt get it down to 1100rpm with backing out knob. Went around again and got it into 3rd gear coming up over a hill it shut off. Coasted down to gas station where i fooled with getting it to start again for the next 20 minutes. Finally got it started again but would not idle and would shut off, kept it throttled and got it home but going up the hill it didn't produce power like it did going up the same hill 40 minutes before this (gas cap off this time to check for it not venting). once i hit a flat spot the rpms jumped back up and the bike pulled but once i hit another hill it just bogged till pretty much coming to a stop. Got to top of hill it just took awhile with wide open throttle in 1st, 2nd gear didnt help at all. Got it in the garage and noticed that there was no fuel in the line and turning it to prime then filled the bowls again, also gas in the tank. the bike had a hard time starting again and if i got it running it wouldn't idle at 1100 rpm without shutting off but when giving it gas it sounded great and responsive. Any ideas on this? carbs are clean, new intake boots and o-rings, new petcock and cleaned gas cap venting hardware. Seems like when cold it pulls hard and runs good but once hot it doesn't keep getting fuel, is that because its already running lean so fuel delivery becomes a issue? Maybe im looking at how fuel delivery operates incorrectly. Another thing i noticed is the headers on 1/4 are not flush to the head like 2/3, not sure what that does but i know it cant be good (seen pic on forum where it shows them being flush) . I will be unbolting clamps and see if i can get them seated to the head, flush. I did do a plug chop coming down hill in third and 1 is tan while 2/3 still white and 4 looking slightly coated in fuel. I will vacuum sync when i get home and see if that helps, in the meantime should i be looking at fuel system faults? Fuel line was a little long i did shorten it up before walking away. Bike ran good through all ranges when it ran GOOD. I also adjusted throttle cable above carbs a few months back never adjusting at throttle side now not sure where it should be or if this is maybe affecting my idle. Cable had some slack in it with about a 1/8 inch of play on throttle before throttle plates started moving, today after getting it home i adjusted the cable tighter so there is almost immediate movement from plates is this correct?

[tom203]

Let's not worry about vacuum sync just yet....we need to keep fuel in bowls when bike is running. There should be enough vacuum from #2 carb throat to feed all 4 carbs,but something is wrong. Just leave petcock in prime spot for now when you are test riding it. But remember to turn petcock to on or res spot when you ain't running.

" Got it in the garage and noticed that there was no fuel in the line and turning it to prime then filled the bowls again, also gas in the tank"

There should be some slack in throttle cable ,before throttle plates start to open. Idle stop screw should hold position (you can feel plates thud as they rest on it.). Erratic idle when warm suggests air leak (or poor bench sync). Good call to get new boots... did you get new boot o-rings too, cuz I don't remember?

[mizz0313]

yes boot o-rings have also been replaced.

[tom203]

yes boot o-rings have also been replaced.

I figured that ,but my memory is poor! Keep at it, your persistence will pay off.

[mizz0313]

Will do! Again, thanks so much for all your help. I will pull it out when i get home, capping off vacuum nipple and test riding. After getting the exhaust headers on 1/4 flush with head.

[mizz0313]

went for a test ride last night and also this morning. When starting off with a cold engine i got nothing but high rpms and no power, after about 5 minutes of running the bike finally gets enough power and pulls amazing. Some breaking up in the higher rpms but pulling fast and blowing my hat off. after about 10 minutes of running the rpms wants to sit a little higher and i do not have enough travel on the idle knob to get it down to where it needs to be. Got it home after testing this morning and couldn't get it to start again, my thoughts are the throttle plates are just not where they should be because it doesn't even start with choke and idle screw backed all the way out (once hot). Would that be a clear sign that the plates are not closed enough? Looking at the throttle plate adjustment screws they look to be screwed in a good bit which would have them open causing more air? I think i need to be bringing them closed and going from there which would be why i cant get it settled down to 1100 once hot, idle screw stops touching plate and idle stays at 2000. Last time i bench synced them i had also did a vacuum sync after but that was also with bad intake boots that i know were sucking or loosing vacuum, didnt bother bench syncing again because i thought i had them where it needed to be. My understanding of the vacuum sync has been confusing, i now think im getting the understanding of it using the gauges. I believe i was opening plates allowing no vacuum instead of the actual building of vacuum in each cylinder. Which i think would be why i cant get it to idle, plates wont close far enough. Also these test were done while running in prime it did ride alot better in prime and doesn't seem to be having that fuel starvation like the previous test rides.

[tom203]

"....my thoughts are the throttle plates are just not where they should be because it doesn't even start with choke and idle screw backed all the way out (once hot). Would that be a clear sign that the plates are not closed enough?"

yes.. your bench sync probably erred - one or more throttle plates preventing the others from closing off enough (and causing idle stop screw to have no job). You probably saw this explanation

http://members.dslextreme.com/users/bikecliff/images/carb_sync_notes.html#A01

note that #3 carb needs to be set first- othes get sync to it. When done, you should have #3's tab resting on idle stop screw with ability to close plates even more if needed.

edit. Try this link

http://members.dslextreme.com/users/bikecliff/images/carb_sync_notes.html

[mizz0313]

Yes that is my issue. As soon as I started reading that link i instantly remembered that I did not follow that procedure. Will pull them off tonight and get it back together to test again. With a lot of thought and mind picking I narrowed it down to this, which also makes sense as to why fuel delivery isn't operating correctly since there is not enough vacuum being applied.

[mizz0313]

Did the bench sync over and also got vacuum gauges hooked up and they seemed to be very close had to adjust 4 a little. Bike idled good around 1000 but once it started getting a little hotter it shut off and wouldn't restart. So I decided to check for spark being these are the stock coils (I have checked these before and they tested good also has relay mod). Got no spark on 1/4 and spark on 2/3 nice blue spark. Obviously working when cold I think that's also a issue of it not wanting to stay running.

[tom203]

You likely have the stock ignitor setup,right? If so, the 550's seem to have the problem unit. Working ok cold, but losing spark when warm, seems to point to an ignitor issue. But check the connections from signal coils up to ignitor,then on to ignition coils, cuz you might have a bad connection.

if this scenario repeats after next cold start and ride, get suspicious.

[mizz0313]

I actually had the ignitor box replaced with dyna after experiencing this previously. That's why my thoughts now point to coil.

[tom203]

Try swapping the ignition coils and see if you now lose spark on 2 and 3 (instead of 1 and 4) when bike warms up. Did you remove spark plug caps and cut back plug wires? Get new plug caps?

[mizz0313]

Did not get new caps but will look into them. I did cut back the wires around the time I was diagnosing the ignitior and having similar issues. I can try swapping out coil I did put spark plug from cylinder one into number two and test for spark and it was there nice and blue right after it not wanting to restart and also hot. My thoughts are a lot of my issues were associated with this coil, posted a photo of plugs previously in this thread and 1/4 looked wet like it had stopped firing which now makes sense. There is a local cycle shop that has one they are willing to sell me for about 30 bucks, I wouldn't be able to get one elsewhere for days and I'm hoping to take advantage of the nice weather here for the next week. Would I be silly to purchase that or does it sound like I'm on the right track with this one being bad?

[mizz0313]

Well I bought another coil and Im not fully sure that was my issue. I do know Old one stopped sparking once hot and this one does still spark once hot but still having a hard time keeping bike at idle. Had it running for about a half hour but it shut off about 4 times during that time while trying to adjust mixture screws at idle. During that span the bike revved and hanged and also a few times idle raced really high, every time getting the idle knob down to 1000rpm it just didn't seem smooth and would want to die. Got it to a point that it revved good came back down nice but still wouldn't hold a idle. Each time shutting off I checked for spark and at the beginning exhaust pipe on one was very cool but after starting again it did start rising in temperature. Had gauges hooked up during this time and all cylinders are very close with one another. am I really just dealing with mixture screws not being set correctly? Had them about 3 turns out and went down as far as one turn but it seemed to hang set there. At this point I'm not sure if this is a mixture issue or ignition/wiring. Only thing I have not done with the bike is replace regulator/rectifier because my charging system test checked out fine. But could the stock rectifier cause my weird ignition issues?