Extreme Rich condition

[chef1366]

It would die on the side of the road and not start for a few minutes.

[HobieSun]

Ok, I bypassed the petcock, not a difference at all. Put back together, readjusted the float level on the fatter side, didn't make a damn bit of difference. Thought that I may have some air leaks between the airbox and the carbs so I sealed it up tight with a few different things, not a damn bit of difference. I can hold my hand over the airbox hole a certain way and get it to rev hard all the way to 10k, if I take my hand off of it, it will bogg, if I put the airfilter box in it will bogg. I have good spark, new plugs, timing matches, getting plenty of fuel through numerous ways, no air leaks, everything has been looked over and/or adjusted. Complete charging system is new, battery, regulator, stator. I am done. Trading the POS in. I have never had anything give me so much S^&! and run so badly.

P.S. Anyone want a 1980GS750L in perfect running condition, that just happens to run ****ty? I have $800 in it.

[frosty5011]

Did you ever replace the 4 rubber plugs that cover the idle jets ?(Not the plugs which covered the mixture screws on top of the carbs.....I saw that there was some misunderstanding about which plug(s) you were talking about in an earlier post).

[HobieSun]

Yes, After I figured out what someone told me awhile ago was incorrect, I replaced the plugs. Thank you though.

[KEITH KRAUSE]

Placing your hand over the airbox hole forces the jets to draw fuel, at least momentarily. The bike will rev better.
Because the bike wasn't running right from the PO, the sky's the limit as to what could be done wrong. You've checked many things but there's still more possibilities.
You may have a vacuum issue here because the carbs seem fuel starved...but at the same time you have black/sooty plugs. It seems like more than one problem.
The airbox may have poor seals or a fit problem somewhere and this would effect vacuum. It could even be the wrong airbox, off a different year/model. I assume you still use the lid.
A poor bench synch/vacuum synch can cause vacuum problems.
I also wonder if the carbs are the correct ones and the jetting is stock, especially the jet needle position. If a PO played around for whatever reason and raised (shimmed) the needles or re-assembled parts wrong, you'd be rich.
These things would explain all your problems. I'm not saying it's these things but there are a lot of things that can go wrong.
A faulty ignitor could explain a poor spark resulting in a "rich" condition.

I don't know why you set the float levels richer with your symptoms.
Also, you said you though you had air leaks between the box and carbs and you "sealed it up tight with a few different things". Not sure what your attempts were but you can't expect a bike to run right with "home fix its". Your words make it sound like you improvised. That generally doesn't work, or certainly not for long when dealing with intake problems.

[Carter Turk]

Isn't stock main jet size 107.5 and you say you have 112's with no pipe or airbox mods? What about the pilots are they 45's or? Wouldn't that be a bit rich on the top end with 112's?

I heard people mention here about the gas tank vent line being clogged and or the gas cap itself. Maybe try with the cap off.

Putting a hand or the airbox is an attempt to richen the mixture temporarily and would lead me to ponder if the tank is supplying enough fuel to the carbs.

How did you bypass the petcock?

I had a black 750ET back in the day, it was my first bike.

My coils went bad and caused my bike to bog at 5000 grand intermittently and foul plugs.

I'd say keep plugging away at it, but don't call it a POS. Not good karma.

I'm just throwing out ideas to chew on.

[HobieSun]

I am not sure about the jet's. I was told by someone that 112.5 are stock. I really dont know what the pilot jets where, I couldn't see a number on them. I don't know about the 112.5, but they said 112 for the main, 170 for the air.

I bypassed the petcock with a funnel and fuel line. IM out of ideas and patience. Thanks for all the help everyone.

[West]

One last thing. Did you check that the floats float?

[HobieSun]

Yeah, I thought of using them as bobbers at one point but I don't think fish like the smell of gas. Don't blame em...

[West]

At least you would get some kind of use out of them.

Other uses:

Hang from auto's rear view mirror like dice.

Use to replace that leaky toilet float.

Stick a toothpick and a triangular piece of paper for a sail & give 'em to your kid as bath toys.

[trispeed]

you should check that the float valve seat o- ring is sealing. It's cheap to replace and if they don't seal ( like mine didn't) the float valve and level is bypassed and fuel just keeps flowing past the seat, regardless of any other issue.

[Mike Curtis]

Mixture Screws

This is a message for Keith , you say the screws should be move out 1 1/2 turns, I just rekitted my '81 GS850GL carbs and turned mine out 2 1/2 turn and it seems to run good with this initial settings. What should I be leary of with these screws out so much & I'm not much of a carb guy.
Do these needle valves provide a fine tuning feature?