1979 gs750e wont idle after adjusting floats

[87-turbo]

first i am new to bikes but not cars and carbs. i bought a 79 gs750e that had sat for 15 years. i lined tank and rebuilt petcock and carbs and installed modified volocity stack pods and the exhaust is stock but has 4 holes in each tip. i first set the float hight at 26mm and i had both the jet needle spacers above the clip. it would idle fine but was way lean and would die when you quick throttled it. pulled off carbs and moved small spacer under e-clip and moved it down 1. spot #2 and put 105 jets in it. set floats to 23 mm. now that it is back on it will start on the choke bit even with the idle screw all the way in it drops to 500 rpm than stalls. if i hold the throttle up it will idle fine. its rich when i rev it now but it revs good. i have adjusted the air piolt every way and still wont idle. what did i do to it that it wont idle now? what should i set my piolt air and fuel screw at? i have read a thousand different ones. i am at 1.5 on each now.

 

[BigD_83]

I see nobody has yet addressed your question of pilot air and fuel screws, so I'll get the party started. Cliff should be along shortly with your mega-welcome

I recall reading that air should be twice the fuel.

My 2 cents would be to go back to stock on everything, and change one thing at a time. The float settings should be stock. Your guess is as good as mine on that one, as there are a number of published numbers for them, but I know a few people on here have been happy at 24mm.

7/8 air and 2 fuel comes to mind as a starting point. EDIT- I see I had that backwards. Thanks for catch, Basscliff

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. 87-turbo,

Your engine sounds lean. With the modified intake you have to use main jets that are four to six sizes larger than stock, raise the needles one or two slots, maybe a bigger pilot jet. The air screws should be about 2x the fuel screws. Use plug chops to check the mixture at all the different throttle openings. You will find the plug chop procedure and links to carb tuning 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

 

[87-turbo]

i got it. went back to 1 on the fuel and 1.5 on the air. after playing with it tonight found out was only running on 1 and 4 all the sudden. cleaned points and readjusted to .018". i had them way to wide. now is idleing great and reving good. now to start plug chopping and tuning. what order plug chop should i do? (idle, 1/4 throttle, 1/2, full)

 

[BassCliff]

Hi,

With VM carbs you start from the bottom (idle circuit) and move up.

Thank you for your indulgence,

BassCliff

 

[MisterCinders]

You should also change those mains to a higher size before trying any chops at upper throttle range.

Stock mains are about 100 for that bike. With open stacks and pipes, you need to move up a few sizes. I'd start with 117.5s and be prepared to move higher. With pods/pipes, I have 122.5s but haven't finalized the main jets yet, so they might come down a size, depending on chop results.

You want to err on the side of rich in the mains, because a lean condition at WoT will burn up valves pretty quickly. So better to overshoot the main jets and then adjust them down to the right size.

 

[87-turbo]

ok, thanks guys, so you think i need that big of jets with just pods and holes drilled in the stock exhaust? ill call z1 this week.