newly rebuilt carb question

[Jeepin it real]

i recently purchased a 1981 GS550L that had sat for the last 10 years with gas in it. i went through the carbs and was shocked by the thick sludgy layer of var nish in these things. i soaked em all and put them all and put them all back on and got it running. but my question is because the petcock on the tank was bad i just used another temporary tank and it runs alright but its erratic. is the petcock that important to the running of the bike or is it my float levels ?

[NeyborDayfid]

Well, it could be a lot of things. Did you replace the O-rings on the intake boots between the carbs and engine? Is the airbox sealed well? I'd spray some starting fluid around the intakes while it's running and see if you get a rise in rpms. Those rubber rings harden and crack and cause all manner if ill conditions.
cycleorings.com is a great place to get a set at a great price.

[BassCliff]

Greetings and Salutations!!

Hi Mr. Jeepin it real,

They are both important but the petcock is a little more so when it comes to proper operation of your motorcycle. A malfunctioning petcock can fill your crankcase with gasoline, not a good thing, or starve the engine. Maladjusted float height can make a cylinder run a little rich or lean, depending on if the level is too high or too low.

Anyway, let me dump a TON of information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...



Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed. I will put you on my prayer list.

Thank you for your indulgence,

BassCliff

[NeyborDayfid]

I understood that you're running the bike with another tank that has a good petcock and it's running erratically. I'd make sure to rebuild, or better yet use a new petcock on the tank you'll be using but if this condition is occurring with the good petcock/tank then I'd say look for leaks and past that check float heights and then needles/seats.
I've tried all the shade-tree workarounds and nothing beats rebuilding the carbs with all new Viton O-rings. It's less than 20 bucks and it's the sure fire way to stop those leaks and save yourself a crankcase full of gasoline.

[Jeepin it real]

Hi Mr. Jeepin it real,

I will put you on my prayer list.

BassCliff

haha any prayers are much appreciated. i have not replaced the intake boot o-rings but i performed a crude vacuum leak test with my hand over the boot while cranking the engine. if it has enough vacuum pressure to turn my hand purple would this be sufficient? i set all the float heights to a tad bit over 21mm which i realize is just a bit lower than the factory specs. i also ordered the petcock diaphragm and should be here in the next day or so. and i would also like to add that i found this site a week ago when i bought the bike and it has been the HOLY GRAIL of information very very helpful. this bike would not be near where it is now without the help of this site

[snicrep5]

[QUOTE= this bike would not be near where it is now without the help of this site[/QUOTE]
amen to that. let me be the first to advise you that you really need to read basscliffs info, especially on carbs and follow it. That way, at least you will have eliminated many sources of problems. And hopefully cured what ever problems you are having.

[frijoles-and-beans]

Do the carb rebuild on Cliff's site. When I first got mine last year, it was running similarly so I did the rebuild. It was a big head-ache for me, but well worth it. Eliminate any problems with your carbs you might have and then go from there.