1978 gs750 jetting

[gs4evr]

I recently purchased a jet kit from 6sigma racing, and they suggested running 117.5 main jets on the middle two carbs and 115s on the outer carbs. My bike has a Mac 4 into one exhaust and K&N filter pods. Is this ok, or should I be running the same size main jets? I'm having jetting problems after installing the exhaust and filters. Also, what is the correct float height? Any help will be appreciated.

[Steve]

Stock main jets are 100, so they are suggesting sizes that are 6 and 7 sizes larger. That is about what I would expect, but not the different sizes. The '83 550 and '84 1150 used different-size mains, but I have not heard of others doing so. Not saying it's a bad idea, just have never heard of it.

According to the information that I have, the correct float height is 23.0 +/- 1.0 mm.


So, you are having "jetting problems" after installing pods and a pipe? Gee, I've never heard of that happening before.
Sorry about the sarcasm, I am just amused every time I hear this.
At least you are asking for help with some intelligent questions.

.

[MisterCinders]

Mixing main sizes seems wrong. Might be compensating for blocked airflow on the outside when your legs get in the way of the pods.

[BassCliff]

Hi,

Some models of these bikes, like the later 1150, came from the factory with the middle two cylinders jetted a little fatter than the outer cylinders. This was for the cooling effect. The middle cylinders would run too hot if the jetting was too lean.

You will find some helpful information in the links below, stock jetting, float height, maybe a manual or "how to" guide. It's your "mega-welcome".

If you are here you probably have a 30 year old motorcycle that needs about 20 years worth of maintenance. In the links below you'll find maintenance lists, documentation, wiring diagrams, "how to" guides, vendor links, tips, tricks, and a whole lot of GS goodness. This is your "mega-welcome". Let's get started.

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!

More links to helpful threads in the forum:
Help! Your Bike Won't Start
DON'T DO THESE THINGS
Help! Your Bike Won't Run Well
Oh God! Pods!


Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[chuck hahn]

I had one..no jets on the bike. Stock ( depending on year manufactured) were either 97.5 or 102.5 If I remember right.. Anyways here some charts that you should store somewhere for future use folks.

http://www.mediafire.com/view/?xzzwz5zzyho#
http://www.mediafire.com/view/?mqywtygzmfu#

http://free-pu.htnet.hr/medo/carbs.jpg