Floats are sinking?

Sinking here!

Hello everyone. I have been reading until my eyeballs are ready to fall out and I have 3 hairs left on my head.
I have inherited this XJ650 project that My son and I have been working on (mostly me) and it keeps fouling plugs at a idle.
I have surgically cleaned the carbs several times. Replaced the needles and seat and when I try to set the float height it floods over. I have tried the hose trick and the measuring method. My first of many questions is what is the weight of a new floats. All 4 weigh in at about 6 ½ grams and it am wondering if the are sinking to the bottom of the bowl. I dropped the floats into a can of gas and they float with just the tips showing about ¼ “ and the metal mounting area straight down. I have the fuel tank on my bench and a hose going to the carbs instead of a plasma bottle. I have the tank height just a few inches above the carbs while testing. Frustrated I turned the carbs upside down and place them on the floor 3 feet below the fuel tank and turned on the fuel to see if they leak. The needles hold the fuel back under the weight of the floats. Problem Floats??????????

Tom 8O

 

when the floats are installed do they move freely? Turn the whole carb rack upside down then right side up and see if they move without binding. Before installing the bowls blow air through the fuel inlet to see if the needles seal. Since your floats do float I suspect a binding problem.

 

Maybe the enrichment plungers may be leaking fuel and flooding the engine. Check to see there is lots of play on the choke cable and the plungers are seated.

MN

 

mlew

I have replace the needles and seat new.
Polished the float pin.
Raised and lower the float with the carb inverted.
I turned the carbs upside down and place them on the floor 3 feet below the fuel tank and turned on the fuel to see if they leak.
The needles hold the fuel back under the weight of the floats.

How much pressure are you talking about on the inlet.

Tom 8O

 

When you turn the carbs upside down, they are going to seal properly provided you have good seats and needles. I will take it you do, as you stated they are new.

If you think about it, you are bypassing the whole reason the floats are there. That is too shut the fuel off at a certain pre-set level. By turning them upside down, you are placing the full weight of the floats on the seats and the only thing you are proving is that you actually have a good seal when the needles are seated. You are doing nothing to prove that the needles are seating when they are supposed to.

This statement, "Replaced the needles and seat and when I try to set the float height it floods over" makes no sense. If you are setting the float height, you should be controlling when it "floods" over. How are you trying to set the float height by measuring? Where are your measurements being taken from? What are you setting the measurements at?

 

If your carbs are not overflowing with the tank connected and three feet above the carbs how have you determined the floats are the culprit here?

Quote: the needles hold the fuel back under the weight of the floats.

Look at two things here:
Enrichment plungers

Vacuum operated petcock.
(if the diaphram is bad you can pull fuel through the vacuum line into the #3 carb holder.) Pull thevacuum line and see if its wet inside with fuel. or leave it unhooked and run the engine on the prime setting on the petcock.

 

The flooding goes on before I install the carbs on the bike.
I have a bench test set up stand.
I just pulled the bowls and raised and lower the needles and the seem free.

 

I have measured the floats and used the clear hose method as well.

 

Hey broke I don't think he's describing his problem right. I think from what he's saying the needles and seats are new and he's gone over the float levels several times but he's still getting too much fuel at idle. Now that I think about it there could be several issues here.

Air jets in wrong place
Pilots and Main jets wrong place
If Mukuni carbs (I don't think thats what he has) Seat o-rings bad and fuel bypassing the seats.
Bad Petcock
Leaking enrichment plungers.


MN

 

Then you don't have the float heights set correctly.

 

So the carbs are flooding over on the bench??

 

thanks MN-Maxims your correct.

 

Oh so they are overflowing on your test bench. Thats alot different then well the first thing come to mind are the floats in upside down?

 

Yes they are flooding on the bench.
#4 leaking first then #1 and so on

 

Remember the floats on those carbs the flat side goes down. Not like car carb floats that the flat side goes up.

 

My floats 15 minutes ago

 

I have been all over the jetting as well, main nozzle 110 in the center and 40 in the other.

 

Ok looks right. How are you measureing the float height?

 

Should be 17.5mm from the gasket sealing area to the bottom of the float with out the little needle being depressed.

 

I Have tried the hose and measuring the fuel height and the measuring the float from the gasket surface ( no gasket installed) method.

 

If thats right then this is what I would do. I would take some tape and tape the floats up and put the fuel line back on and see if the fuel is leaking around the seats. Leave the bowls off and set them back in your jig and see what happens

 

I know this is a messy deal but we need to find out if the fuel is truely leaking through the float needles or around the seats.

 

I will try taping up the floats. But wouldn't that be the same as turning the carbs upside down and watching for leaks??

 

In the past a few members have had issues with the seats not fitting right and fuel leaked around the outside and also the towers they screw into have had small cracks and fuel has leaked that way too.

 

Yes I guess you could try that upside down way. So witht he bowls off what do you see??

 

Every thing looks goods. which brings me back to the float weight and maybe it is not lifting up and turning off the fuel.
My original question was what should the float weigh?
my com in 6.5 grams.

 

I think I would PM Rick and see if he knows the weight. Or PM Chacal he would know for sure.

MN

 

Thanks you all for quick responses. I have no doubt that there is answer coming.

Tom

-----------------------------------------------------------------------
1982 Maxim 650 , a work in progress

 

Where are you taking your measurement to the float itself? There are two refence points you need to get correct. One is the gasket surface, the other is the point on the float itself. Since you have tried the hose method, what reading are you getting at the hose in relation to float bowl mating surface?

 

I can't get a good reading correctly is what I am saying.
I let the bowls fill up and they start leaking out of the front air jet out the air box side of the carb.. that is way above the time they should have shut off at.
Which tell me that the needles remain unclosed.
I show a picture of the drizzling carb on a previous post.

Tom

 

Do these carbs have a vent line in between carb 1 & 2 and 3 & 4 up near the tops? These carbs look like the kind on my Ninja and the PO had plugged the lines not knowing what he was doing, turn the gas on the tank it would piss right out each carb since the vents were plugged off.

 

I haven't seen anything that looks like it was plugged off for any reason. All looks factory. The fuel just runs up the bowl to the external air jets and once to the top air vent for the vacuum piston.
Where would I look for a plug in the carb?

Tom

 

Post a picture of you taking a float height measurement. Not one using the hose, the one where you actually adjust the little tang on the floats and measure how high the floats sit in relation to the gasket surface of the carb.

 

Broke_Dirty_Maxim

I am using the tail end of my calipers set to 17.5 MM.
I measured from the gasket mating surface to the molded line in the float.
I have done them at higher levels as well but still runs out of the external air jet.

Tom
:?:

 

As I am looking at your first picture, I would say that you need to hold the measuring device at a 90 degree angle to the gasket surface instead of the angle you have it now. If you check exactly what you are showing at 90 degrees to the gasket surface, I think you will see that your float heights are actually at something like 20mm.

Also, keep in mind that the recommend float height setting is only a recommendation for stock carbs with OEM parts. If you replaced your needles and seats with different manufacturer parts, the actual measurement may need to be different. Try bending one of the tabs flush and see if that carb stops leaking. If it does, I would take it from there and just use trial and error to get that one right, and then try to replicate the measurement between the rest of carbs. By that point, you should be able to perform the clear hose check and make the finer adjustments for each carb.

 

I wouldn't trust the Kits.
I'd put an absolute mirror finish on the Float Valve Body's
Wrap 3 Q-Tips together, tightly and chuck them in the drill.
Rouge or Ultra-Finish Compound.

Geometry:
Look at the Float Pin hanging on the Tang in the Float.
If the Float Pins Wire Clip prevents the Pin from being centered, ...
and the Pin is "Cockeyed" ...
Modify the wire
Center the Float (add washers to the Hinge Pin ... Yes, you can get them that small!)

 

Just a update on this project of ours.

I have been following all the advice that was given to me.
After all that they still over flow when I bench tested them until I would
tap on the sides of the carbs with something metallic. Then I could check the levels OK. They were hanging but never could find out what. I reinstalled the carbs and now testing them to see how they do on the bike.

Hopefully

Everready_tom :roll:

 

I had a problem with one of my needles getting stuck cockeyed before it had a chance to seat properly. I didn't find this out until after I had made sure everything else was good measurement wise.

To fix it, I took a regular q-tip, cut it in half and chucked it in a Dremel tool with some metal polish and polished the inside of the needle seat walls. I used Wenol metal polish. But if you have old fashioned toothpaste, not the newer gel types, that should work just fine. Also, you can chuck the q-tip in any old drill. It doesn't have to be a Dremel tool.

 

I think Polishing the Inside Diameters of Float Valve Bodies is a very important process when servicing the Carbs, ...

Or ...

Before installing NEW Ones that have been Manufactured in the Far East.

Geometry:

The Float Pins that are coming in some Kits have Wire Clips that might need modifying.
If the Pin is "Hanging - Cockeyed" ... off the Wire Clip and not centered perfectly ... make it right.
Sometimes just reversing the way its hung does the trick.
If the actual FLOAT Assy ... has too much side-to-side ... shim the hinge.
They make Flat Washers small enough to put on the Hinge Pin.

 

Just a update on this project of ours.

Reinstalled the carbs.
Put a set a set of vacuum gauges on it to balance the intake flow.
Started to adjusting the pilot screws. Started at 2 3./4 turns out.
(Right turn lean left turns rich.)
Results
OK Idle.... fluttering between 2000 and 3500 RPM and slow response when accelerating until 4000 RPM and then it takes off and smooths out.
The Idle is a about 100 to 200 RPM high after a short jaunt of 3 miles and drops down below 1050 RPM for a couple of seconds and settles back to 1050 and sound OK then.
I have over 50 miles on these plugs and the engine is running OK as described above. Did 85 MPH on the highway and accelerates OK after 4000 RPM.
Pulled the plugs and they are still powered black. Before this I couldn't get but a couple of miles before I had no idle and the plugs would fowl out.
SO I am getting happier that I am still riding for 50 miles.

Everready_Tm

 

Oh
One thing more! I am now running 91 Octane fuel in the tank.

Everready_Tom