The carb problems never end

[Tiny]

1981 gs750lx
After market pipes
Pod filters

It ran last fall but was lagging on throttle up so I thoroughly cleaned the carbs and flushed the tank and filled with fresh fuel then regapped the plugs at .024

Now it only starts if tank is set to prime, then I can return it to normal setting... Will only stay running if I hold the choke about 2500-3000 rpms... I know the second carb/intake boot is leaking because when I spray carb cleaner on it the idle increases.

Last week we were able to get it to idle on its own at 2500 rpms with no choke. But now it won't even do that.

If it has to be set to prime to start then not enough vacuum or too much air? How can I diagnose and solve either of those?

If I turn mixture screws out does that give it more fuel or more air? They're at 2 1\4 turns out now.

Any thoughts or ideas would be very appreciated.

[Cipher]

If your boots are leaking why not remove that variable?
To not do that is like elevating divination of chicken bones to a religious status.

A leak would not necessarily even be a constant in the equation.

[Tiny]

Yup, doing that next... Had to break for lunch... 8)

[Steve]

If I turn mixture screws out does that give it more fuel or more air? They're at 2 1\4 turns out now.

Actually, you will add BOTH, but the overall mixture will be richer.

Just for fun, set them at 3 full turns out to see if that helps. When it's running slowly back them off until it runs best. You may find that 2 1/2 to 2 3/4 will be good.

Did you winterize the bike properly, or at all? If you didn't, it's possible that you need a mild cleaning of the pilot jets and passages.

.

[Guest]

#2 boot is also the cylinder vacuum is picked up from for yourpetcock

[Tiny]

That explains why it wouldn't run until started with prime.

[Tiny]

Another question...

My mixture screws were for this bike were mixed up with others... Another mysterious helper cleaning up my bench... Are the mixture screws 13\16 in length or the longer 1 1\16 inch that I think belong to 850 carbs?

[Nessism]

Carb rebuild tutorial linked in my signature. You might want to read through it to see if you missed anything. Lots of guys try to short cut by not unganging the carbs but there is a high frequency of failure from that.

Oh, and since you have pods you should get a Dynojet kit or similar. And real deal K&N pods or UNI's or Ape pods are highly recommended. Emgo pods are worse than drinking PBR.

[habsdoc]

Hey, I happen to really like PBR.

[Guest]

When I bought my '83 the po had one of his employees "rebuild" the carbs. I bought it non running.
I had no problem working on single carbs, 3 wheelers, quads and cars but 4 carbs intimidated me. So I took them to a mechanic and he got them running but not quite.
Then I found GSR and started from scratch. I took mine to Steve to have him take them back to stock, adjusted the valves, replaces the intake o-rings and bought a Carbtune. The bike runs as it should and there are no mysteries now.
Follow these guys advice to the tee and you won't go wrong, except the PBR thing.

[JJ]

Hey, I happen to really like PBR.

Really? I imagine that's what horse p!ss tastes like. LOL!

[Guest]

1981 gs750lx
After market pipes
Pod filters

What is your jetting like? Needle setting? With pods and aftermarket pipe you are going to be somewhere around 3-3.5 turns out on the mixture screws and the main jets will be many sizes larger than stock. If you don't have adjustable needles (and you most likely won't in the US) then you need a jet kit. A stage 3 Dynojet kit will work and makes life much easier.

And real deal K&N pods or UNI's or Ape pods are highly recommended. Emgo pods are worse than drinking PBR.

+1 to both. I would only ever use the K&N's or the APE pods.

Really? I imagine that's what horse p!ss tastes like. LOL!

+1 to that as well.


Mark

[Charlie G]

Carb rebuild tutorial linked in my signature. You might want to read through it to see if you missed anything. Lots of guys try to short cut by not unganging the carbs but there is a high frequency of failure from that.

Oh, and since you have pods you should get a Dynojet kit or similar. And real deal K&N pods or UNI's or Ape pods are highly recommended. Emgo pods are worse than drinking PBR.

Tiny,

If you haven't already looked through the tutorial in Nessism's signature, I strongly recommend it. These guys know there stuff. Personally I prefer Whiskey and above 90 proof .

[Tiny]

It has a stage 3 dynojet kit... I started at 2 1\4 and worked up to 3 turns out with no change except seems harder to start

[Tiny]

Yeah, I love that tutorial... I almost have it memorized I've used it so many times