'80 SG... First Start...

[crazy steve]

Steve, you're 100% sure no crossover passage, otherwise you need the rubber plugs. You are running 120 or smaller mains and 42.5 pilot and 185 air, correct? The height of the needle/seat should not matter as long as the float hight is somewhere in the 23MM range.

Yep, 100% sure as I specifically looked for that passage as the carbs were apart when I got them and I would have needed to order the plugs. The only thing in that hole for the emulsion tube is the locating pin. All the jetting is dead stock (110 mains, 42.5 pilot, and 185 air) as I'm using a stock exhaust and airbox. I'm really starting to think those floats ain't floatin' like they should, so I'll check externally with the tubes off the float bowl drains.

[bikerphil]

I highly doubt your plastic floats aren't floating, check 'em if you want. I would suspect the wrong diaphram needles/ e-tubes though if you are saying the carbs were in pieces. I'd check the numbers on those parts just to make sure they're correct. The wrong ones will definitely ruin your day.

Edit: your pilots have the 6 air bleed holes in them correct?

[petejw]

[ I would suspect the wrong diaphram needles/ e-tubes though if you are saying the carbs were in pieces. I'd check the numbers on those parts just to make sure they're correct.[/QUOTE]

that wouldnt stop it from running at idle or causing it to flood at idle, only when the slide starts to raise and the butterflies have opened past the off idle ports that the needle would come into affect.

[bikerphil]

Yep Pete, you're right on that, it should idle fine as long as the needle is long enough to make it down into the jet. Too short and wouldn't it let constant fuel thru the main though?

[petejw]

i dont think it would matter,

i know from memory the main jet can be removed from the
carb and the bike will still run at idle,
its been a long time since tech,
but the butterflys need to be open for enuff air to flow
thru the carb pass the top of the main jet nozzle (emulsion tube)to suck the fuel up.

i agree with u regarding the floats, they shouldnt be a problem,
and if there set at 23mm then that should be close enuff for the engine
to run without flooding.

for there to be 4 wet plugs there must be something in common with
all 4 carbs to cause it to run rich and cause flooding.

[crazy steve]

Yeah, the problem isn't how it runs after it starts, it's getting it started. I got it to run twice; first time, I turned on the petcocks, waited a bit to get fuel into the bowls, then tried it. It immediately started, but then flooded out before I could touch the throttle. It's obviously too rich, as if I hold the throttle fully open it will try to start but not quite. The second time I got it to run, I closed the petcocks, tried to start it and it caught when (I assume) the bowl fuel level dropped enough. It started and ran for about a minute or so (even took throttle good) until it started running out of fuel. Low fuel, went lean, rpms went up until it died.

I'm pretty convinced the float levels are off, and the stock setting isn't even close... I'll post what I find after checking float levels with the tubes...

You gotta understand Phil, if it's something weird that's never happened to anyone else, it'll happen to me... that's the kind of luck I have.

[cywelchjr]

Well, let me ask this; do those plastic floats get 'fuel logged' over time? These are undoubtably original floats....

Never heard of them doing that. That said, have you don't the fuel leak test just to be sure? And did you make sure that you don't have the cross passage in those carbs?

[DGXSER]

Sounds like you have the 81 model carbs. I have yet to have any problem with the plastic floats and all have seemed original.

I do not know who stated those needles would be an "upgrade", but I would switch those back and try it again.

[skids]

Steve, those pins on the float needles can be suspect. Sometimes they can even stick in a depresses position, or I suppose have different spring pressures.

Another thought is that I have heard members say that the bank of carbs should be tilted when measuring float heights to take the differences of the spring-loaded pins out of the equation. I suppose you would have to blow into the fuel supply hoses and tilt the bank of carbs until you just get the floats to seal. A lot of hastle...

If you can get the manometer method to cross-reference the measured float heights you could conceivably be able to calibrate proper float heights for each carb and eliminate the need for the manometer method for future adjustments.

[DGXSER]

Sorry, I forgot to mention setting float height. For me anyway, I have always simply had the carbs resting on the diaphram lids, used my gage to set them to 23mm and the bike runs good. Admittedly, I have never gone through the hassle of the manometer setup of the fuel level. And I have not had any issues getting a bike to start and run decent after cleaning up the carbs. If you have set them to roughly 23 mm, then the bike should definitely start and run, any small adjustment that could be made from the manometer might help it run better at different revs, but I doubt it would keep it from starting.

[jetmechmarty]

An old bike mechanic who helps me from time to time told me that the floats do absorb fuel over time and not float as well.

That being said, wouldn't that condition turn the fuel off early? Or...is my logic upside down?

Marty (in Tampa)

[natemoen]

An old bike mechanic who helps me from time to time told me that the floats do absorb fuel over time and not float as well.

That being said, wouldn't that condition turn the fuel off early? Or...is my logic upside down?

Marty (in Tampa)

If they don't float well then the fuel would stay on longer than it should.

[crazy steve]

An old bike mechanic who helps me from time to time told me that the floats do absorb fuel over time and not float as well.

That being said, wouldn't that condition turn the fuel off early? Or...is my logic upside down?

Marty (in Tampa)

If the floats are sinking too much, that will raise the fuel level in the bowls; which is what I think is happening.

I'll take a shot at this after breakfast....

[crazy steve]

Well, after double-and-triple checking everything with the carbs off the bike, I just dunno...

Float levels looked very close when checked with the tube off the drain, so that's not it. I tried 'simulating' the engine vacuum with my shopvac to see if I was getting a fuel out places it shouldn't be coming out of, and noticed that the top of the emulsion tube (where it protrudes from the bore) was getting wet. So it may be the jet needles... or can these get worn and leak? The only other thing I can see is I compared the side-drain bowls to the bottom-drain versions and those are slightly different (besides the drain type). The bottom-drain are larger in every dimension except at the gasket face; I know that shouldn't make any difference...

I'm having a hard time getting anything done today, 'cause my dog decided this year he doesn't like fireworks.. Every time something goes boom, he gets totally underfoot (and at 90+ lbs, that's a lot under foot!) and I have to calm him down. We'll both be glad when the 4th is past....

[skids]

As you know, the emulsion tubes are supposed to be air bleeds. They get their air from the pressed-in air jet in the inlet bell of the carb. That jet can be easily plugged. I think if no air gets in, the fuel can really draw upward. (Like holes in a soda straw) Also, if the carbs are not properly above the fuel pools, gas levels can rise. This is more of an older xs11 issue than the 80 and 81's because of the way they are vented.

I think there is also a vent from the inlet bell to the mating surface of the carbs (at least the older ones) but I am not sure how it is supposed to work (maybe for the starter jets?). I think that if the punch-outs in the gasket are not removed that vent has no hope of working.

You might drain each carb into a container and compare the cc's of gasoline in each carb...