petcock woes....

[morbidphil0622]

Hello everybody, I have a question about my 83 gs750 es... I have been having some issues at startup. When the chocke is on the exhaust will shoot a few flames out which is pretty dang cool I must say, but I think something isnt right. The idle was a bit funny as well. I turned the screws on top of the carbs out a bit, well out a lot (they are out almost 4 turns now). I think this is a bit much but it keeps the idle right where I want it, and the flames have gone away for now. Is this an ok setting for theese screws to be on or is this a sign of another problem with the bike? Lately I have been getting a constans smoke coming out of the exhaust. It started out white and now that the screws have been fondled it (the smoke) has turned a bit darker... Am I running way too rich?

Last but not least, I was riding today and she started bogging down really bad on all throttle positions. so I pulled over to see what was up.. I had a full tank of gas and all of my lines were in good shape. I remembered a thread not too long ago, so I turned the petcock to the reserve position, bike ran outstanding after I gave my wrist a few twists.. Bike also ran great in the prime position, so I pit it to the ON pos. and WHAM! She went back to running like crap. I am just assuming than I need a new petcock here, would be pretty insaine not to replace, and it might explain my poor gas mileage. Could the screwed up petcock be causing this smoke from the exhaust? I have a V&H 4 in 1 pipe so I really cant tell which side it comes from, but I can tell you that there is a tiny bit of gas in the petcock vaccum line, and that aint cool...

Sorry for such a long post, I just needed to gather all of the facts from my other posts to get myself on the right page. I have a compression test kit coming in the next few days so I will post my results as soon as I get them... I will also do a plug chop test when I get off of work tomorrow morning, I hope.. You all have been a great help to me as I someday hope to be with you ... Thanks for everything!!!! Jason...

[mark]

You vacuum line sucking gas could create much of the problem you describe. Its gotta be fixed so you might as well start there.

Not sure what you mean by the "screws on top the carbs". Do you mean the air screws?

[Billy Ricks]

The gas in the vacuum line means the diaphram is leaking. You're getting way too much fuel to cylinder #2 because of it. That's what is likely causing the smoke. As for the mixture screws being 4 turns out, that's pretty much off the jet and running full rich. You can get a petcock rebuild kit off Ebay cheap. If I were you I'd pull the carbs and clean them up, especially the pilot circuit. Once the pilot circuit is cleaned up you shouldn't need to be more than 2-2 1/2 turns out on the screws.

[morbidphil0622]

Cool, thanks... That helps me out more than you know. If this is my problem than I am so relived... I will just suck it up and buy a new petcock setup, does anybody know if I can swap to a non vaccum fed simple on off type petcock? It might not be possible but I figured it would be a lot easier in the long run. The vaccum hose actually feeds into cyl# 3 but I get what you are saying. To answer your question, yes the screws I am referring to are the air screws. I will most likely pull the carbs and clean the crap out of them this weekend, I might as well put some new bowl gaskets on there while I am at it.. Thanks, so very very much I dont know what I would do without this place and you all.. Well I guess I would be driving huh? Jason

p.s. sorry to sound so motodumb but I am 22 and havent had much bike experience, so I hope you understand...

[Billy Ricks]

Cool, thanks... That helps me out more than you know. If this is my problem than I am so relived... I will just suck it up and buy a new petcock setup, does anybody know if I can swap to a non vaccum fed simple on off type petcock? It might not be possible but I figured it would be a lot easier in the long run. The vaccum hose actually feeds into cyl# 3 but I get what you are saying. To answer your question, yes the screws I am referring to are the air screws. I will most likely pull the carbs and clean the crap out of them this weekend, I might as well put some new bowl gaskets on there while I am at it.. Thanks, so very very much I dont know what I would do without this place and you all.. Well I guess I would be driving huh? Jason

p.s. sorry to sound so motodumb but I am 22 and havent had much bike experience, so I hope you understand...

Go to Pingel's website and check out their petcocks. If I were you I would replace at least the 0-rings on the float seats. You have to pull the float to get the seats out. Be very careful and support the tower the float pins run through. There is a guy by the name of Robert Barr who posts here occasionally that can supply a complete set of o-rings cheap.

[dietcokeking]

Checking to see if your petcock vacuum diaphram is bad is quick and easy. You need to pinch off the vacuum hose thoroughly, then ride the bike on PRIME to see if your problems cease. Remember to turn the petcock back to ON or RESERVE when you stop so you don't flood the thing when parked (leaving it on PRIME will continue to feed fuel to the carbs under gravity, and the float needles could allow fuel to seep into the carb/airbox/engine). Auto parts stores can sell you a pair of plastic fuel line pincher-pliers for a couple of dollars, or you can rig something. I padded a small pair of vicegrip-type needle nose pliers when I had to do this.

There are complete replacement petcocks for a lot of models on Ebay, like this: http://cgi.ebay.com/ebaymotors/SUZUK...20408900QQrdZ1

You could check with these guys to see what they have for your bike (or check the OEM part number against their listings).

[morbidphil0622]

Wow, that was the exact petcock that I was looking at this morning and planned on buying about 10 minutes from now.. I did the test like you said and it was exactly as planned. Bike bogged out in On and res positions. It ran great in prime... I changed my oil today and I cant really tell if it smells like gas or not.. The oil is only about 2 weeks old but I had the valve cover off the other day to fix a stripped hole. Anyways thanks everybody and I will let you know how it goes...