If you know GS Carbs. Please help

[althomas101]

In my experience your better off having the bike run slightly rich. Cold start ups are easier, and there is a smoother transition to the needle circuit. You don't really want the bike to "Pop" as that is really lean running, your "PuP" is what you want to hear on deceleration. If you rev up the bike and it goes right back to idle without hanging (lean), or dipping below idle (rich) then your spot on. Also if the bike is too rich it will stumble on accelleration if it has been idling for a while like at a long red light. Rich symptoms get worse the hotter it is outside, lean get better. I hope that helps.

[pearljam724]

The bike normally would be a little lean if the intake o-rings were leaking air. Maybe someone in the past made some adjustment to account for that. Then, when you corrected the o-ring problem, the bike began to run rich. Maybe your needles have been shimmed if it's running rich at a throttle opening of more than a 1/4 turn.

Good point which was the case, before I ordered new n installed. Until then the problem was much worse. Was acting as if it was running on 1 cylinder which is no longer the case since I changed them. Good point about some someone adjusting something prior as well

[pearljam724]

The bike normally would be a little lean if the intake o-rings were leaking air. Maybe someone in the past made some adjustment to account for that. Then, when you corrected the o-ring problem, the bike began to run rich. Maybe your needles have been shimmed if it's running rich at a throttle opening of more than a 1/4 turn.

all of you made great points which I'll take into account and appreciate.

[pearljam724]

Bike Is running pretty damn good right now. The cool weather made a huge difference. I'm going to leave it alone.

[Dave8338]

Bike Is running pretty damn good right now. The cool weather made a huge difference. I'm going to leave it alone.

So it IS in fact running a tad rich. There are a few conditions that would make a CV carb run rich in the RPM range that you mention.

1. Shimmed jet needles
2. Air mixture screw adjustment as Steve pointed out and nicely illustrated.
3. Hard and shrunken 25-year old internal carb O-rings allowing fuel past the metering points.
4. Dirty or over oiled air filter.

Take your pick of the four I mention OR...better yet, check the jet needle height position (visual inspection) it should be in the third notch down from the top or up from the bottom. The middle position...

Lightly seat your mixture screws and then back them out about 2 turns.

Replace the o-rings in the carbs as those of us who have provided you with all this "anal relief", have ALL done this several times in the past and may just know a thing or 4500 things, about the carbs on these bikes.

Either replace your air filter if it needs it and or clean and lightly oil your filter if you have a K&N drop in, like I do.

Good luck

[Steve]

Take your pick of the four I mention OR...better yet, check the jet needle height position (visual inspection) it should be in the third notch down from the top or up from the bottom. The middle position...

I did not see any mention of his location, but if he is in the US, his '87 carbs won't have adjustable needles, so there is no "third notch down".

.

[Dave8338]

I did not see any mention of his location, but if he is in the US, his '87 carbs won't have adjustable needles, so there is no "third notch down".

.

Good to know. Was that change made in 1985-86 ?

[Kaiser Sosei]

Pretty sure anything '80 and newer does not have adjustable needles in the US. At least not stock.

[pearljam724]

Im from the states. Pa to be exact. Who am I kidding. I'm going to tear them apart this winter and replace the o rings. Only thing that it can be. I knew I should have replaced them. But, once opening the carbs up and inspecting the bowls, needles and jets. It appeared that someone without a doubt in my mind. Had them cleaned, recently. Assuming, if someone went that far they would have changed the rings while they were at it. Definately not the air filter. One thing I need to question. If adjusting the 2 air mixture screws, synching the carbs. That isn't going to correct the mixture. Synching carbs does not do that. All synching them is going to do is smooth any idle. I don't have an idle problem. Above idling, synching the carbs will not change the air fuel mixture. Therefore, not correcting any rich problem. It's definately not running lean as the idle immediately drops down to proper idle rpm's once I let off the throttle. If it were running lean or I had a vaccuum leak anywhere else. It would not do that. I've addressed everything that I know to address. Other than the internal carb o rings.