#3 #4 Plugs completely black after 1 mile

[CA]

Ok here are the facts over the past two days:

-58 miles, 3.5 gallons
- below 3k rpm she sputters and hesitates
-over 3k rpm she is a rocket all the way to redline especially 5k+
-turned down idle mixture screws about 3/4 turn on both #3 and #4; no change
just didn't want to force them down anymore
-after adjusted mixture screws I put in new plugs and drove literally less than 2 miles to my brothers and #1 and #2 are clean #3 and #4 are completely black and look even a little moist

My idiot guess is maybe i measured my float level on those two wrong? Or could it be something as simple as I messed up the fuel hose wiring? Remember it could be something dumb as I am not that mechanical.

Somehow fuel must be getting dumped in there, hopefully that is what is causing my hesitation in low rpm since it would seem to bog it down.

What should I do next?

PS - I had rebuilt my carbs and synched them last week; we got the sync pretty darn close I believe.

Thanks.

[bikerphil]

First, what year is your bike?
Second, is it a Standard or a Special?

[XJOK2PLAY]

Float levels...

When you measured your float levels... did you have the gasket in place or removed? Makes a big difference, and is easy to do. (Gasket should be removed.) Float could be bad (sinking), or sticking needle? !2 mpg... that's expensive! Sounds like somethings causing her to flood.

[CA]

1979 Special

I believe I removed the gasket, but perhaps I did not remove it for the 3 and 4? I replaced the float valve and needle with new ones. I had the total rebuild kit...obviously didn't come with new floats, and I didn't use the long needle thing...I just wanted to make sure it wasnt something else before I ripped out the carbs once again to check the floats...

ya 17 mpg is not what I was expecting...lol.

Sorry i tried to put my bike model in my signature...

[DGXSER]

Its in there now.

I would verify your float heights, If you can, you could make an adaptor to fit the float bowl drain to attach a tube to it and check the fluid height in the bowls. To some, it would be easier than pulling the carbs back off.

Otherwise, did you replace all of the jets in all of the carbs? what kits did you get? Who did you order from?

[bikerphil]

Also, make sure the fuel lines are connected to the lower T fittings between the carbs. The upper ones are vents that connect to the airbox. Float height is 25.7 mm with carbs upside down and gasket removed. Brass floats can get pinholes in them and not 'float'.

[CA]

here is what I bought from georgefix:
"4 BRAND NEW PREMIUM CARB kits for 1979 XS 1100 F and XS1100 SF SPECIAL.

EACH KIT COMES WITH 137.5 MAIN & 42.5 PILOT

You are bidding on a set of 4 kits. EACH SET OF CARB KITS COMES WITH ALL GASKETS AND O-RINGS, IDLE MIXTURE SCREW, METERING NEEDLE, MAIN AND PILOTS JETS, FLOAT NEEDLE AND SEAT ASSEMBLY. . "

Like I said the only thing I didnt use was the metering needle (the really long thing)

To me just taking out the carbs sounds easier since I am much better at something that I have already done...rather than something new, but maybe Ill look up how to do the adapter.

The floats looked okay to me, is there any way to check if they "float" when you take them out?

So is the consensus incorrect float height right now??? Anthing else to check while I have them out? Guess I'll just have to take off the float bowl...

[DGXSER]

Float height will definitely effect the richness of the mixture. It is also something that is very precise, and these carbs are picky about.

Georgefix tends to know what he is doing with the carbs on these. He steered me right anyway. Mine did not come with new needles, but most tend to find that they do not wear out very often, so not replacing them is very common from what I have read here.

So now, Checking the floats, you can put them in some gasoline or other type of fluid and see if they sink a bit. Look for other threads on this, brighter minds than mine have given a run down on testing floats here before.

While your in there, check that the tang that stops the float from falling to far is set the same on all of them as well and has not broken off any of them. Also check your needle seats and valves for cleanliness. Since you say your octy is cutting off the fuel when not running, your floats may not be closing off on that side when running making te fuel height very rich in both carbs. IF you got some junk out of your petcock and ran it on prime or if your fuel line got torn up putting it on the Tee (DAMHIKIJK) you might have got some gunk in the valve seat and the valve not seal off. Other than that, make sure all your jets are in correctly. There was a recent case where someoen had a similar problem, opened up the float bowl and the pilot jet was laying loose in the bowl.

[CA]

No problems that i can see

Ok so I took the carbs out tonight, and the floats all seem to be the same height, I don't know how anyone could get them any closer without special tools. they are all about 26mm high, they look level when you eyeball them. ANd all of them floated in gasoline...so I dont understand, why would 3 and 4 be running so rich!!!! I checked the valves and pilot jets...everything looks fine and the exact same on all four carbs...

THe question of the hour...should I simply lower/ which would be raising...the #3#4 carb floats to compensate for the richness?? I dont know what else to do!?!? In looking at the mixture screw in the hole it was obvious that it was farther down in #3 and #4 than in 1 and 2...so theyre must be something wrong with 3 and 4...im stumped..HELP!!

[CA]

Electrical?

Could it be electrical, maybe not enough juice running through the lines?? (I don't know anything about that...

Or mabe air filter related? I just put in a new one...im so confused!

[dbeardslee]

CA - If it was electrical, you would most likely notice it on #2 and #3, #1 and #4 as that is the pairing for the coils. #1 and #2, #3 and #4 share fuel lines. If you're running the stock exhaust (4/2) and it hasn't been run in a while, you might check to make sure you don't have some kind of obstruction in the exhaust. Mice have been known to climb up in there and build nests, although you would think in 58 miles it would have blown that out. Also make sure you have baffles on both sides if it's 4/2.

Have you checked your compression? When these things sit for extended periods, the seating surfaces of the valves can get pitted. Doubt that's what's doing it though with the problem you describe. Still it's good to know what your psi's are doing.

Also, make sure your carb vent lines are clear.

And last but not least, when you cleaned your carbs did you make sure to clean the little jet in the bottom of the bowls? If you strip the paper off a bread tie the wire works nicely for cleaning it out. It's the little hole in the bottom of the bowl. If you stick the tube on a can of carb cleaner in that hole and pull the trigger you should get a nice energetic atomized stream coming out of one of the holes on the flange. Make sure it's pointed away from you when you do it - carb cleaner in the eyes REALLY hurts .

When you're seeing a problem below 3k, it's generally somewhere in the idle circuit, which is what that little hole in the bottom of the bowls connects to. Additionally, when you set your float heights do it without the gaskets and measure from the gasket surface to the top of the floats on BOTH sides of the float - sometimes they get bent. When I set mine I measure them with an adjustable carpenter's square. I set it 1mm more than what I want, so that when it's where I want it I can just see a little light between the square and the float (so as not to push them down). You really need to use something that hangs over the float - holding a ruler on the gasket surface and trying to eyeball it is really difficult.

On a '79 you should have brass floats. Check them for leaks (shake 'em around and see if you can hear fluid inside, or put them in some liquid and see how high they float compared to the others) and check that the sides aren't pinched in - they should be kind of rounded on the sides.

Just some more stuff for you to think about .

[DGXSER]

Checking float heights

I think it was Skids that gave me the suggestion of a go-no go gage for float heights. I took an old credit card and layed out the upper and lower heghts on it and cut out notches for each, one on each side. Then I just sit it on thegasket surface and let it hang over the float first with the max height and make sur eI see light, then the min height and make sure it rubs at least a touch.

Like dbearslee stated, the electrical on these bikes is linked outside cylinders, and inside cylinders. So TYPICALLY, electrical will show up that way. Since you have both carbs that are fed from the same fuel line acting up, it seems fuel related. This why I suggested the float valves.

Did you pull your floats off, remove the valve, and then unscrew the seat and check for any little bity pieces of anything in there? It does not take much to keep the needle from seating (DAMHIKIJK). I quit using auto fuel line because it would get little pieces scraping off when I put the line on the Tees and make it through my screens and lift my float valves. HTH

[CA]

Yes, Yes, and Yes....

Yes I checked the floats to see if they float in gasoline, yes I took of the float valve and seat and looked down in there...nothing. Yes, I cleaned that brass tube which goes down to the bottom of the bowl and cleaner shot out the side, and into my eye!

I haven't checked my compression, I have no idea how to do that, but it sounds like more money on a new tool...don't like that.

How could it be air related, with too much fuel? I'll double check the vent hose on that right side...

Maybe I will get help with the float height measuring, but I know I have to be pretty darn close...if they are within half a mm shouldn't that be ok, I mean I am getting a huge difference between the carbs. Should I just go ahead and lower the culprits by a 1.5mm??

But I am still stumped!? HELP!!

[DGXSER]

I would not lower them that much, they should all be the same. If the vent tube on that side is clogged it could be causing you problems. Make sure the vent Tee is not clogged and the path to the bowls is open. Spray more cleaner in there. I would try putting the carbs on without that vent tube on them. It is really there to let you recycle fumes back to carbs. Most folks that run pod filters either leave them open or put a small filter on it. Did you make sure to run plenty of carb cleaner through your air passages as well, your pilot air jet clean? To much fuel can mean not enough air.

Other than that, if it were me, i'd put them back together and try it again.

[CA]

Ok...

Well i guess I just put them back on after checking the vent tubing and its T, Ill just run some compressed air through it. This doesn't make sense at all!!