1982 GS550L lean

[Guest]

started a post in the performance/tuning section but it should probably be posted here. Having issues with lean condition on my gs550l on cylinders 1/3/4 with pilots turned out 4 turns. Bike has been converted completely back to stock. Being honest i did everything in the newb section from carb tear down to valve adjustment and looking over all air intake parts. I ordered O-rings from Robert Barr but made a mistake with size so i put bike back together. Just ordered correct size after spraying carb cleaner and getting a very small idle change only on 3/4 side. Days ago I had carb off again after having issues with getting bike to idle when setting mixture screws, did bench sync while they were off. Jets are all stock and i know the carbs are clean, also set float bowl to correct spec after seeing they were not set correctly causing no fuel. Took it out this morning at 4 turns on pilots it idled nice but in 1st trying to take off it needs a lot of throttle to even start moving. In 2nd once moving it seems nice at part throttle gets moving and then has a flat spot, wide open it pulls nice and hard but that's after rpm come down for a second. After pulling hard in 3rd I killed engine and checked plugs 1 rich(was lean yesterday when tested) 2 golden color, 3/4 lean. Can't go higher than 3rd where I live unless on big road, does that make plug chop ineffective?

Should I be adjusting float to allow more fuel or change some jets? With all the research I've done these pilots shouldn't be out that far. While waiting for correct O-rings i will be looking over my air intake system again, i did weatherstrip airbox cover and there is a rubber o-ring between airbox and secondary airbox so i believe that is sealed too but will double check. Please let me know what you think. If i should change jet sizes i will need help choosing. I may adjust float bowls to have more fuel either way, cant hurt. I made a airbox cover to ride before i got the factory cover in the mail, that cover was pretty restrictive and i now have too much air with factory cover so im going to put that on and see if it riches up enough to turn pilots back in and do more testing.

[mizz0313]

here again to ask for suggestions from the gs gods. Got Intake o rings installed redid bench sync and also vacuum sync, adjusted pilot screws by ear (hope I did it correctly) all after adjusting float height to .900 to rich mixture. Bike idled nice and also had great power through all circuits so I took it to work. About a mile out it started stalling but started right up, continued on and a quarter mile from work it lost all power with full throttle it wouldn't pull anymore and also shut off while making a turn so I had to coast it the rest of the way. Got to work let it sit about a hour and it fired right up idled nice and redlined. Leaving work it was very troublesome had a hard time getting any power and going up hill it barely moved with full open throttle then would start losing even more power till or eventually shut off. Let it sit it would start and I would go a little further till it shut off again. Did this all the way home took about 2 hours for a 15 mile drive. PLEASE PLEASE any help or suggestions are welcome. During trying to get it home I adjusted the mixture screws from 2-3.5 turns hoping it would make a difference and it didn't. I've dipped carbs and gone through them again multiple times but does this sound like a carb issue? I'm ready to call it quits with it so ANY SUGGESTIONS WILL HELP! ANY! Lol

[Nessism]

Sounds like an ignition issue or maybe the petcock. Mixture screws don't cause the types of issues you mention here.

[mizz0313]

Okay I will try petcock it's the one thing I have not changed on the bike. It has dyna and stock coils but does have spark once hot. But once hot, bike does act like fuel is shut off/restricted. Thanks

[mizz0313]

Would I still get these symptoms from a bad petcock that is set to prime?

[tom203]

Would I still get these symptoms from a bad petcock that is set to prime?

Maybe if the petcock was internally clogged.. But gas cap might not be venting (so fuel flow is restricted). Try loosening the cap and go for ride.

[mizz0313]

just updating that i still haven't got the chance to get the bike out with the rain here in PITT, i will try to get it out today with gas cap loosened and see if if it drives any better once warm. I also need to try syncing the carbs closer. Made a manometer that is a little twitchy and still trying to get how it works down pat. will let you guys know how it goes. Thanks

[mizz0313]

Soaked gas cap parts to clean, tested petcock and its bad. Fuel flows in ON and RES without vacuum applied.

[tom203]

Skip rebuilding it- just get new, bunch on ebay right now for $40 to $50 . Note outlet directions and make sure that it comes with the o-ring. Here's a typical

http://www.ebay.com/itm/Suzuki-fuel-gas-petrol-petcock-gs1100-gs1000-gs850-gs750-gs650-gs550-gs450-gs300-/292198150430?hash=item44085df11e:g:03oAAOSwDFNWFXo8&vxp=mtr

[mizz0313]

ordered petcock from the link you posted, will have new petcock here tomorrow to install. One question i have been trying to get answered through research is "what symptoms do you get from a petcock that constantly flows"? I have become familiar with the way these petcocks are supposed to work and have found main symptoms of them failing, but not symptoms of them failing in this manner. One thing i have noticed while working on this bike with a bad petcock is i see a pulsing from fuel line while bike is running, I assumed that was the vacuum system doing its job but its not. Will I still get fuel starvation like issues with a petcock that flows in on and res without vacuum applied, what happens when vacuum is applied? I do know i tried running the bike in prime when having issues and it didn't make a difference from what i was able to tell. Its getting replaced either way but figured id ask to have a better understanding of whats going on with my bike or if i should still be looking elsewhere also to fix my issues. Thanks

[tom203]

getting these things running right is a step by step process. Your vacuum petcock needs to functioning correctly... flowing fuel at all times will overwhelm float needle seats and likely lead you to overcompensate somehow. Install the new petcock and then reset the mixture screws carefully to 3 turns out and go from there.

The petcock mounting screws need a special washer underneath their head. These washers have rubber bonded to metal - when tightened they insure a tight seal. A good hardware store should have them in plumbing section....1/4 inch size probably will work with the 6mm screw. Bring the screw to store to get a good fit!

[mizz0313]

IMG_1497.jpgBack again! Got the petcock on and it is working correctly, vacuum sync carbs using gauges. Had bike running and after getting a hanging idle I checked idle screws and plugs, screws we about 2 turns out and the 1/4 plugs were kinda brown with fuel while 2/3 were white and ashy. Go out this morning hoping to ride after tuning screws, and I couldn't get bike to start right away no matter how much choke. Took plugs out after cranking didn't seem to have fuel on them. Went out 3 turns in idle screws and got bike started. while adjusting screws it didn't have much change on the idle bike idled okay but when given throttle rpm dipped and bike wanted to shut off would keep running if i let go of throttle. When it would dip low I would touch choke and it would rev back up. But it did this no matter where I had idle screws set, turn out to 3 turns after pulling plugs and when given throttle it still dipped if I eased on throttle it revved up but only to about 2500 with the sound of not enough power to rev higher and would hang a little. Back at idle if I blipped it would dip again unless I was really easy on it. Are my carbs still gummed up? Last time tearing carbs apart I unganged them and sprayed carb cleaner through idle circuits and choke holes and watched fluid shoot out, I have dipped these carbs already. Ive gone so far with this bike not knowing anything at all about them when I bought it but can't seem to figure out the lean/rich conditions

[tom203]

Firstly..... This in your cold start

"and I couldn't get bike to start right away no matter how much choke. Took plugs out after cranking didn't seem to have fuel on them."

I'd suspect the "choke" is not supplying enough fuel up to carb throats... With all your poking and blowing carb passages, did you clean out the passage in the fuel bowl itself, cuz this often gets clogged?

At this point, before your gauge carb sync, I'd doublecheck my bench sync carefully - done right, this will get you real close with all carbs sorta happy... engine should rev eagerly from idle provided enough mixture is available as throttle is openned.

[mizz0313]

yes when bowls were off i watched carb clean stream from float bowl holes to across the room, unless they are clogged again. i will be taking carbs off again then. thanks

[tom203]

Lucky you! Make sure that "choke" lever pulls out plungers on carbs 1/2 inch fully (I just checked mine)-otherwise cold start won't be quick!
Inspect/ compare mixture screws - make sure their o-rings and washers are intact- and look for blockage from old parts jammed in carb throat orifices.

. once you get these carbs running right, they will stay that way for a long time with with little additional effort.