turning air screw

[goggleboy]

I noticed that adjusting my pilot air screw on my 4th cylinder carb doesn't effect engine idle. I did more than 1 full turn either way and nothing happened. why not? I turn #2 and #3 and it has an effect. Sometimes #1 has an effect, but not as quick.
Why would this be?

[hampshirehog]

One turn may no be enough if it's way out to start with. have a look at the carb sticky to see the standard settings and tune from there.

Either that or your synch is way our or you have a blocked pilot jet.

[Larry D]

You may have broken the tip of the screw off in the carb body.

[Guest]

What year?

[goggleboy]

What year?

1978C. I just dipped, cleaned and re-assembled the carbs.
The needles were clean, and not broken. The air screw isn't sharp
at the end anyways right?
I did a bench sync from Bikecliff's VM rebuild guide.
Its poping a bit, backfired once, bogs when I open the throttle, then catches. Also, doesn't reach over 80mph...??? The powerband is not
consistent all the way up

[Guest]

Valves adjusted?
Carbs sync'ed?

[Guest]

Airbox or pods?
Stock jetting?

[goggleboy]

Air box, weatherstripped and sealed. sprayed for leaks, none with the boots or carb/air box mating surface. new carb boots n' orings too. valve clearances are in spec, however the only thing I haven't done is a good sync. I've tried to bench sync them, and tune the fuel and air screws. I notice a slight difference when I mess with the screws.
Power is just not all the way there. I'm going to re-check timing as well.
Plugs are grey on the outside cylinders, and a little darker on the inside.
When I open the throttle (quickly but not super fast) it bogs bogs bogs, until i let up. If I don't let up it'll bog all the way down and shut off.


if its running lean, do I screw OUT the pilot fuel screw or screw IN the pilot air screw? (vice versa for rich)

this is been like that battle from 300 or lord of the rings.

[Big T]

if its running lean, do I screw OUT the pilot fuel screw or screw IN the pilot air screw? (vice versa for rich)

Since you have a stock set up, you should be out 7/8 turn on the fuel and 2 on the air to start

And, to answer your question - out is more - out on the fuel = more fuel, out on the air=more air

So,if you're lean, out on the fuel and in on the air

Wait, you have points? When were the points and condensors last changed?

[goggleboy]

Wait, you have points? When were the points and condensors last changed?

No, dyna S electronic ignition with 3ohm dyna green coils, but that's a good question. I haven't had a chance to check the timing yet.
I just turned out the fuel screw about an 1/8 and turned the air screw in
a bit. A tad Better, but its still boggy all around. It feels okay from 2000-4500rpm then starts loose power a little bit. It as if Im holding the throttle open and it should be going faster but its not. I wish I could make noises on here and send them via forum. " bawww bawww wwahhhhhh" then it catches and rmp's climb.. but only after I have fully opened the throttle.
I'll be in 5th gear full throttle and it won't break 85mph , about 6000rpm

I rode my neighbors 74' Honda CB550 today and it made me cry how my GS
was slower ...I don't want to cheat on her

[Big T]

Okay, but what are your screws set at???

Hmm, is your vacuum line hooked up - from #3 carb to the petcock?

Try giving it about 1/4 choke and see if the symptoms ease

Did you use carb kits when you rebuilt your carbs?

[goggleboy]

Okay, but what are your screws set at???

Hmm, is your vacuum line hooked up - from #3 carb to the petcock?

Try giving it about 1/4 choke and see if the symptoms ease

Did you use carb kits when you rebuilt your carbs?

Yeah hose is coming from petcock to #3 carb, and no I didn't use rebuild kits. I did order orings from cycleorings, but reused stock jets and needles.

I tried giving it a little choke, idle went up (obviously). It made from-the-get-go bogging worse, but it seemed like on the higher side of the tach, it pulled well. I'm at a loss. the only thing I could think of is checking the timing, and actually using a sync tool.

[Guest]

Coud still have a clpgged pilot jet orifice. Something else is causing the top and problem though

[goggleboy]

Coud still have a clpgged pilot jet orifice. Something else is causing the top and problem though

dang, I literally licked the carbs clean with dipping them and spraying them, and made sure my jets were clean.
Would it be a float problem? Because after all that I started it up and within a few minutes #2 carb spit out fuel from the overflow nipple for a few seconds then shut off. FFFFFF!!!!! I'm going to drop that bowl and turn it on pri and see what happens. Last time I checked, I only got 23MPG... way to low. My plugs were black. After the cleaing and adjusting, the plugs are more grey. good, but I haven't had a chance to check MPG yet. something tells me its the same

[earlfor]

You can't adjust carburetors that are badly out of synch. You can try, but it ain't a gonna happen. I would be willing to bet the vacuum levels on your carbs are all over the scale. Do a vacuum synch. That is step #1 in carb adjustment and tuning.
Until the carbs are all drawing the same volume of air, you can't adjust crap.

Earl