petcock?

[Matt]

I have an 81' GS 750 Ex. I realized it originally had a petcock with a horizontal diaphragm. Could this be the reason it starts starts dieing in the higher R's, & runs crappy? It looks like someone has fooled with the carbs. Can someone please tell me what the factory settings should be?

[BassCliff]

Greetings and Salutations!!

Hi Mr. Matt,

Has the intake or exhaust been modified from stock? ANY changes in intake or exhaust usually require jetting changes to compensate for added air flow. For example, if you have removed the stock airbox and installed individual pod filters, you are now running "lean" (less fuel and more air in the air/fuel mixture ratio) and at higher revs the engine is running out of juice, starving for fuel. Or are you using an inline fuel filter? This can also cause fuel starvation. Of course, a bad petcock is common on these older bikes too.

Clean carburetors are also a must. If you don't know the complete history of the bike, the "mega-welcome" contains maintenance tasks which should be completed in order to ensure a safe, reliable, well running vintage GS motorcycle. You'll find "how to" guides for most maintenance tasks on my little website.

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.

Thank you for your indulgence,

BassCliff

[tom203]

I have an 81' GS 750 Ex. I realized it originally had a petcock with a horizontal diaphragm. Could this be the reason it starts starts dieing in the higher R's, & runs crappy? It looks like someone has fooled with the carbs. Can someone please tell me what the factory settings should be?

"horizontal diaphragm" ? what have you got now, and does it have lever? Of course, someone fooled with carbs- it's a given! many things could cause fuel starvation, how does it run otherwise? That Basscliff guy has more info on this subject than you can digest in one year, so take advantage!

[Matt]

Thanks for the warm welcome. You have a ton of useful information. I'm the proud owner of 2 GS's. An 81 GS750Ex & an 83 GS1100G. I will be putting up some pics soon.

[Matt]

Yes the diaphragm sits horizontally under the switch instead of vertically & behind. I never seen one like that, but thats what it shows in the manual. I would really like to know factory setting I know it's typically 1 1/4 turn out & so fourth. But I don't want to just go at it like a monkey how the last guy did. I still can't find factory specs, even in Basscliffs extensive library.

[sedelen]

I'm afraid most of us have never heard of a horizontal diaphram. They say a picture is worth a 1000 words, in this case it can clear up the miscommuication.

How to post pictures on GSR

http://members.dslextreme.com/users/bikecliff/images/how_to_post_pictures.pdf

[tom203]

Yes the diaphragm sits horizontally under the switch instead of vertically & behind. I never seen one like that, but thats what it shows in the manual. I would really like to know factory setting I know it's typically 1 1/4 turn out & so fourth. But I don't want to just go at it like a monkey how the last guy did. I still can't find factory specs, even in Basscliffs extensive library.

OK. the parts diagram shows two petcocks- lever style and leverless, the latter being very unpopular. But what " factory setting " are you refering to? the petcock either works or doesn't.Basscliff's site has info overload regarding carb specs -your carbs aren't unusual.